Imported from libpng-1.0.4-pre1.tar
diff --git a/pngvcrd.c b/pngvcrd.c
new file mode 100644
index 0000000..57d3b1a
--- /dev/null
+++ b/pngvcrd.c
@@ -0,0 +1,3888 @@
+/* pngvcrd.c - assembler version of utilities to read a PNG file
+ *
+ * For Intel CPU and Microsoft Visual C++ compiler
+ *
+ * libpng 1.0.4 - September 17, 1999
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998, Intel Corporation
+ * Copyright (c) 1998, 1999 Glenn Randers-Pehrson
+ *
+ * Contributed by Nirav Chhatrapati, INTEL Corporation, 1998
+ * Interface to libpng contributed by Gilles Vollant, 1999
+ *
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#ifdef PNG_ASSEMBLER_CODE_SUPPORTED
+
+static int mmx_supported=2;
+
+void
+png_read_filter_row_c(png_structp png_ptr, png_row_infop row_info,
+   png_bytep row, png_bytep prev_row, int filter);
+
+static int mmxsupport()
+{
+  int mmx_supported_local = 0;
+
+  _asm {
+    pushfd            //Save Eflag to stack
+    pop eax           //Get Eflag from stack into eax
+    mov ecx, eax      //Make another copy of Eflag in ecx
+    xor eax, 0x200000 //Toggle ID bit in Eflag [i.e. bit(21)]
+    push eax          //Save modified Eflag back to stack
+
+    popfd             //Restored modified value back to Eflag reg
+    pushfd            //Save Eflag to stack
+    pop eax           //Get Eflag from stack
+    xor eax, ecx      //Compare the new Eflag with the original Eflag
+    jz NOT_SUPPORTED  //If the same, CPUID instruction is not supported,
+                      //skip following instructions and jump to
+                      //NOT_SUPPORTED label
+
+    xor eax, eax      //Set eax to zero
+
+    _asm _emit 0x0f   //CPUID instruction  (two bytes opcode)
+    _asm _emit 0xa2
+
+    cmp eax, 1        //make sure eax return non-zero value
+    jl NOT_SUPPORTED  //If eax is zero, mmx not supported
+
+    xor eax, eax      //set eax to zero
+    inc eax           //Now increment eax to 1.  This instruction is
+                      //faster than the instruction "mov eax, 1"
+
+    _asm _emit 0x0f   //CPUID instruction
+    _asm _emit 0xa2
+
+    and edx, 0x00800000  //mask out all bits but mmx bit(24)
+    cmp edx, 0        // 0 = mmx not supported
+    jz  NOT_SUPPORTED // non-zero = Yes, mmx IS supported
+
+    mov  mmx_supported_local, 1  //set return value to 1
+
+NOT_SUPPORTED:
+    mov  eax, mmx_supported_local  //move return value to eax
+
+  }
+
+//mmx_supported_local=0; // test code for force don't support MMX
+    //printf("MMX : %u (1=MMX supported)\n",mmx_supported_local);
+
+  return mmx_supported_local;
+}
+
+/* Combines the row recently read in with the previous row.
+   This routine takes care of alpha and transparency if requested.
+   This routine also handles the two methods of progressive display
+   of interlaced images, depending on the mask value.
+   The mask value describes which pixels are to be combined with
+   the row.  The pattern always repeats every 8 pixels, so just 8
+   bits are needed.  A one indicates the pixels is to be combined,
+   a zero indicates the pixel is to be skipped.  This is in addition
+   to any alpha or transparency value associated with the pixel.  If
+   you want all pixels to be combined, pass 0xff (255) in mask.  */
+
+/* Use this routine for X86 platform - uses faster MMX routine if machine
+supports MMX */
+
+void
+png_combine_row(png_structp png_ptr, png_bytep row,
+   int mask)
+{
+   //int mmx_supported=0; // another test code for remove MMX in this routine
+   png_debug(1,"in png_combine_row_asm\n");
+   //if (mmx_supported==2)
+   //    mmx_supported=mmxsupport();
+
+   if (mask == 0xff)
+   {
+      png_memcpy(row, png_ptr->row_buf + 1,
+   (png_size_t)((png_ptr->width *
+   png_ptr->row_info.pixel_depth + 7) >> 3));
+   }
+   else
+   {
+    switch (png_ptr->row_info.pixel_depth)
+      {
+   case 1:
+   {
+      png_bytep sp;
+      png_bytep dp;
+      int s_inc, s_start, s_end;
+      int m;
+      int shift;
+      png_uint_32 i;
+
+      sp = png_ptr->row_buf + 1;
+      dp = row;
+      m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+      if (png_ptr->transformations & PNG_PACKSWAP)
+      {
+    s_start = 0;
+    s_end = 7;
+    s_inc = 1;
+      }
+      else
+#endif
+      {
+    s_start = 7;
+    s_end = 0;
+    s_inc = -1;
+      }
+
+      shift = s_start;
+
+      for (i = 0; i < png_ptr->width; i++)
+      {
+         if (m & mask)
+         {
+      int value;
+
+      value = (*sp >> shift) & 0x1;
+      *dp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
+      *dp |= (png_byte)(value << shift);
+         }
+
+         if (shift == s_end)
+         {
+      shift = s_start;
+      sp++;
+      dp++;
+         }
+         else
+      shift += s_inc;
+
+         if (m == 1)
+      m = 0x80;
+         else
+      m >>= 1;
+      }
+      break;
+   }
+   case 2:
+   {
+      png_bytep sp;
+      png_bytep dp;
+      int s_start, s_end, s_inc;
+      int m;
+      int shift;
+      png_uint_32 i;
+      int value;
+
+      sp = png_ptr->row_buf + 1;
+      dp = row;
+      m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+      if (png_ptr->transformations & PNG_PACKSWAP)
+      {
+         s_start = 0;
+         s_end = 6;
+         s_inc = 2;
+      }
+      else
+#endif
+      {
+         s_start = 6;
+         s_end = 0;
+         s_inc = -2;
+      }
+
+      shift = s_start;
+
+      for (i = 0; i < png_ptr->width; i++)
+      {
+         if (m & mask)
+         {
+      value = (*sp >> shift) & 0x3;
+      *dp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+      *dp |= (png_byte)(value << shift);
+         }
+
+         if (shift == s_end)
+         {
+      shift = s_start;
+      sp++;
+      dp++;
+         }
+         else
+      shift += s_inc;
+         if (m == 1)
+      m = 0x80;
+         else
+      m >>= 1;
+      }
+      break;
+   }
+   case 4:
+   {
+      png_bytep sp;
+      png_bytep dp;
+      int s_start, s_end, s_inc;
+      int m;
+      int shift;
+      png_uint_32 i;
+      int value;
+
+      sp = png_ptr->row_buf + 1;
+      dp = row;
+      m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+      if (png_ptr->transformations & PNG_PACKSWAP)
+      {
+         s_start = 0;
+         s_end = 4;
+         s_inc = 4;
+      }
+      else
+#endif
+      {
+         s_start = 4;
+         s_end = 0;
+         s_inc = -4;
+      }
+      shift = s_start;
+
+      for (i = 0; i < png_ptr->width; i++)
+      {
+         if (m & mask)
+         {
+      value = (*sp >> shift) & 0xf;
+      *dp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+      *dp |= (png_byte)(value << shift);
+         }
+
+         if (shift == s_end)
+         {
+      shift = s_start;
+      sp++;
+      dp++;
+         }
+         else
+      shift += s_inc;
+         if (m == 1)
+      m = 0x80;
+         else
+      m >>= 1;
+      }
+      break;
+   }
+     case 8:
+        {
+        png_bytep srcptr;
+        png_bytep dstptr;
+        png_uint_32 len;
+        int m;
+        int diff, unmask;
+
+        __int64 mask0=0x0102040810204080;
+
+        if (mmx_supported)
+        {
+        srcptr = png_ptr->row_buf + 1;
+        dstptr = row;
+        m = 0x80;
+        unmask = ~mask;
+        len  = png_ptr->width &~7;  //reduce to multiple of 8
+        diff = png_ptr->width & 7;  //amount lost
+        _asm {
+          movd    mm7, unmask        //load bit pattern
+          psubb   mm6,mm6            //zero mm6
+          punpcklbw mm7,mm7
+          punpcklwd mm7,mm7
+          punpckldq mm7,mm7          //fill register with 8 masks
+
+          movq    mm0,mask0
+
+          pand    mm0,mm7            //nonzero if keep byte
+          pcmpeqb mm0,mm6            //zeros->1s, v versa
+
+          mov             ecx,len    //load length of line
+          mov             esi,srcptr //load source
+          mov             ebx,dstptr //load dest
+               cmp   ecx,0 //lcr
+               je    mainloop8end
+
+mainloop8:
+          movq    mm4,[esi]
+          pand    mm4,mm0
+          movq    mm6,mm0
+          pandn   mm6,[ebx]
+          por             mm4,mm6
+          movq    [ebx],mm4
+
+          add             esi,8       //inc by 8 bytes processed
+          add             ebx,8
+          sub             ecx,8       //dec by 8 pixels processed
+
+          ja              mainloop8
+mainloop8end:
+
+          mov             ecx,diff
+          cmp             ecx,0
+          jz              end8
+
+          mov             edx,mask
+          sal             edx,24      //make low byte the high byte
+
+secondloop8:
+          sal             edx,1       //move high bit to CF
+          jnc             skip8       //if CF = 0
+          mov             al,[esi]
+          mov             [ebx],al
+skip8:
+          inc             esi
+          inc             ebx
+
+          dec             ecx
+          jnz secondloop8
+end8:
+          emms
+          }
+        }
+        else /* mmx _not supported - Use modified C routine*/
+        {
+          register unsigned int incr1, initial_val, final_val;
+          png_size_t pixel_bytes;
+          png_uint_32 i;
+          //if ((mask != 0x0f) && (mask != 0x33))
+          register int disp = png_pass_inc[png_ptr->pass];
+          int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+          pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+          srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+             pixel_bytes;
+          dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+          initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+          final_val = png_ptr->width*pixel_bytes;
+          incr1 = (disp)*pixel_bytes;
+          for (i = initial_val; i < final_val; i += incr1)
+          {
+          png_memcpy(dstptr, srcptr, pixel_bytes);
+          srcptr += incr1;
+          dstptr += incr1;
+          }
+        } /* end of else */
+
+        break;
+        }       //end 8bpp
+
+        case 16:
+        {
+        png_bytep srcptr;
+          png_bytep dstptr;
+          png_uint_32 len;
+        int unmask, diff;
+
+        __int64 mask1=0x0101020204040808,
+            mask0=0x1010202040408080;
+
+        if (mmx_supported)
+        {
+          srcptr = png_ptr->row_buf + 1;
+          dstptr = row;
+
+        unmask = ~mask;
+        len     = (png_ptr->width)&~7;
+        diff = (png_ptr->width)&7;
+        _asm {
+          movd    mm7, unmask       //load bit pattern
+          psubb   mm6,mm6           //zero mm6
+          punpcklbw mm7,mm7
+          punpcklwd mm7,mm7
+          punpckldq mm7,mm7         //fill register with 8 masks
+
+          movq    mm0,mask0
+          movq    mm1,mask1
+
+          pand    mm0,mm7
+          pand    mm1,mm7
+
+          pcmpeqb mm0,mm6
+          pcmpeqb mm1,mm6
+
+          mov             ecx,len    //load length of line
+          mov             esi,srcptr //load source
+          mov             ebx,dstptr //load dest
+               cmp   ecx,0 //lcr
+               jz    mainloop16end
+
+mainloop16:
+          movq    mm4,[esi]
+          pand    mm4,mm0
+          movq    mm6,mm0
+          movq    mm7,[ebx]
+          pandn   mm6,mm7
+          por             mm4,mm6
+          movq    [ebx],mm4
+
+          movq    mm5,[esi+8]
+          pand    mm5,mm1
+          movq    mm7,mm1
+          movq    mm6,[ebx+8]
+          pandn   mm7,mm6
+          por             mm5,mm7
+          movq    [ebx+8],mm5
+
+          add             esi,16      //inc by 16 bytes processed
+          add             ebx,16
+          sub             ecx,8       //dec by 8 pixels processed
+
+          ja              mainloop16
+mainloop16end:
+
+          mov             ecx,diff
+          cmp             ecx,0
+          jz              end16
+
+          mov             edx,mask
+          sal             edx,24      //make low byte the high byte
+
+secondloop16:
+          sal             edx,1       //move high bit to CF
+          jnc             skip16      //if CF = 0
+          mov             ax,[esi]
+          mov             [ebx],ax
+skip16:
+          add             esi,2
+          add             ebx,2
+
+          dec             ecx
+          jnz secondloop16
+
+end16:
+          emms
+          }
+        }
+        else /* mmx _not supported - Use modified C routine */
+        {
+          register unsigned int incr1, initial_val, final_val;
+          png_size_t pixel_bytes;
+          png_uint_32 i;
+          register int disp = png_pass_inc[png_ptr->pass];
+          int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+          pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+          srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+             pixel_bytes;
+          dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+          initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+          final_val = png_ptr->width*pixel_bytes;
+          incr1 = (disp)*pixel_bytes;
+          for (i = initial_val; i < final_val; i += incr1)
+          {
+          png_memcpy(dstptr, srcptr, pixel_bytes);
+          srcptr += incr1;
+          dstptr += incr1;
+          }
+        } /* end of else */
+
+        break;
+        }
+      case 24:
+        {
+        png_bytep srcptr;
+          png_bytep dstptr;
+          png_uint_32 len;
+        int unmask, diff;
+
+        __int64 mask2=0x0101010202020404, //24bpp
+            mask1=0x0408080810101020,
+            mask0=0x2020404040808080;
+
+          srcptr = png_ptr->row_buf + 1;
+          dstptr = row;
+
+        unmask = ~mask;
+        len     = (png_ptr->width)&~7;
+        diff = (png_ptr->width)&7;
+
+        if (mmx_supported)
+        {
+        _asm {
+          movd    mm7, unmask         //load bit pattern
+          psubb   mm6,mm6             //zero mm6
+          punpcklbw mm7,mm7
+          punpcklwd mm7,mm7
+          punpckldq mm7,mm7           //fill register with 8 masks
+
+          movq    mm0,mask0
+          movq    mm1,mask1
+          movq    mm2,mask2
+
+
+          pand    mm0,mm7
+          pand    mm1,mm7
+          pand    mm2,mm7
+
+          pcmpeqb mm0,mm6
+          pcmpeqb mm1,mm6
+          pcmpeqb mm2,mm6
+
+          mov             ecx,len     //load length of line
+          mov             esi,srcptr  //load source
+          mov             ebx,dstptr  //load dest
+               cmp   ecx,0
+               jz    mainloop24end
+
+mainloop24:
+          movq    mm4,[esi]
+          pand    mm4,mm0
+          movq    mm6,mm0
+          movq    mm7,[ebx]
+          pandn   mm6,mm7
+          por             mm4,mm6
+          movq    [ebx],mm4
+
+
+          movq    mm5,[esi+8]
+          pand    mm5,mm1
+          movq    mm7,mm1
+          movq    mm6,[ebx+8]
+          pandn   mm7,mm6
+          por             mm5,mm7
+          movq    [ebx+8],mm5
+
+          movq    mm6,[esi+16]
+          pand    mm6,mm2
+          movq    mm4,mm2
+          movq    mm7,[ebx+16]
+          pandn   mm4,mm7
+          por             mm6,mm4
+          movq    [ebx+16],mm6
+
+          add             esi,24      //inc by 24 bytes processed
+          add             ebx,24
+          sub             ecx,8       //dec by 8 pixels processed
+
+          ja              mainloop24
+mainloop24end:
+
+          mov             ecx,diff
+          cmp             ecx,0
+          jz              end24
+
+          mov             edx,mask
+          sal             edx,24      //make low byte the high byte
+
+secondloop24:
+          sal             edx,1       //move high bit to CF
+          jnc             skip24      //if CF = 0
+          mov             ax,[esi]
+          mov             [ebx],ax
+          xor             eax,eax
+          mov             al,[esi+2]
+          mov             [ebx+2],al
+skip24:
+          add             esi,3
+          add             ebx,3
+
+          dec             ecx
+          jnz secondloop24
+
+end24:
+          emms
+
+          }
+        }
+        else /* mmx _not supported - Use modified C routine */
+        {
+          register unsigned int incr1, initial_val, final_val;
+          png_size_t pixel_bytes;
+          png_uint_32 i;
+          register int disp = png_pass_inc[png_ptr->pass];
+          int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+          pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+          srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]
+             *pixel_bytes;
+          dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+          initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+          final_val = png_ptr->width*pixel_bytes;
+          incr1 = (disp)*pixel_bytes;
+          for (i = initial_val; i < final_val; i += incr1)
+          {
+          png_memcpy(dstptr, srcptr, pixel_bytes);
+          srcptr += incr1;
+          dstptr += incr1;
+          }
+        } /* end of else */
+
+        break;
+      }       //end 24bpp
+    case 32:
+      {
+      png_bytep srcptr;
+      png_bytep dstptr;
+      png_uint_32 len;
+      int unmask, diff;
+
+
+
+      __int64 mask3=0x0101010102020202,       //32bpp
+          mask2=0x0404040408080808,
+          mask1=0x1010101020202020,
+          mask0=0x4040404080808080;
+
+      srcptr = png_ptr->row_buf + 1;
+      dstptr = row;
+
+      unmask = ~mask;
+      len     = (png_ptr->width)&~7;
+      diff = (png_ptr->width)&7;
+
+      if (mmx_supported)
+      {
+      _asm {
+        movd    mm7, unmask           //load bit pattern
+        psubb   mm6,mm6               //zero mm6
+        punpcklbw mm7,mm7
+        punpcklwd mm7,mm7
+        punpckldq mm7,mm7             //fill register with 8 masks
+
+        movq    mm0,mask0
+        movq    mm1,mask1
+        movq    mm2,mask2
+        movq    mm3,mask3
+
+
+        pand    mm0,mm7
+        pand    mm1,mm7
+        pand    mm2,mm7
+        pand    mm3,mm7
+
+        pcmpeqb mm0,mm6
+        pcmpeqb mm1,mm6
+        pcmpeqb mm2,mm6
+        pcmpeqb mm3,mm6
+
+        mov             ecx,len       //load length of line
+        mov             esi,srcptr    //load source
+        mov             ebx,dstptr    //load dest
+
+            cmp   ecx,0 //lcr
+            jz    mainloop32end
+
+mainloop32:
+        movq    mm4,[esi]
+        pand    mm4,mm0
+        movq    mm6,mm0
+        movq    mm7,[ebx]
+        pandn   mm6,mm7
+        por             mm4,mm6
+        movq    [ebx],mm4
+
+
+        movq    mm5,[esi+8]
+        pand    mm5,mm1
+        movq    mm7,mm1
+        movq    mm6,[ebx+8]
+        pandn   mm7,mm6
+        por             mm5,mm7
+        movq    [ebx+8],mm5
+
+        movq    mm6,[esi+16]
+        pand    mm6,mm2
+        movq    mm4,mm2
+        movq    mm7,[ebx+16]
+        pandn   mm4,mm7
+        por             mm6,mm4
+        movq    [ebx+16],mm6
+
+        movq    mm7,[esi+24]
+        pand    mm7,mm3
+        movq    mm5,mm3
+        movq    mm4,[ebx+24]
+        pandn   mm5,mm4
+        por             mm7,mm5
+        movq    [ebx+24],mm7
+
+
+        add             esi,32        //inc by 32 bytes processed
+        add             ebx,32
+        sub             ecx,8         //dec by 8 pixels processed
+
+        ja              mainloop32
+mainloop32end:
+
+        mov             ecx,diff
+        cmp             ecx,0
+        jz              end32
+
+        mov             edx,mask
+        sal             edx,24        //make low byte the high byte
+
+secondloop32:
+        sal             edx,1         //move high bit to CF
+        jnc             skip32        //if CF = 0
+        mov             eax,[esi]
+        mov             [ebx],eax
+skip32:
+        add             esi,4
+        add             ebx,4
+
+        dec             ecx
+        jnz secondloop32
+
+end32:
+        emms
+
+         }
+      }
+      else /* mmx _not supported - Use modified C routine */
+        {
+          register unsigned int incr1, initial_val, final_val;
+          png_size_t pixel_bytes;
+          png_uint_32 i;
+          register int disp = png_pass_inc[png_ptr->pass];
+          int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+          pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+          srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+             pixel_bytes;
+          dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+          initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+          final_val = png_ptr->width*pixel_bytes;
+          incr1 = (disp)*pixel_bytes;
+          for (i = initial_val; i < final_val; i += incr1)
+          {
+          png_memcpy(dstptr, srcptr, pixel_bytes);
+          srcptr += incr1;
+          dstptr += incr1;
+          }
+        } /* end of else */
+
+      break;
+      }       //end 32bpp
+
+
+      case 48:
+      {
+      png_bytep srcptr;
+      png_bytep dstptr;
+      png_uint_32 len;
+      int unmask, diff;
+
+      __int64 mask5=0x0101010101010202,
+          mask4=0x0202020204040404,
+          mask3=0x0404080808080808,
+          mask2=0x1010101010102020,
+          mask1=0x2020202040404040,
+          mask0=0x4040808080808080;
+
+      if (mmx_supported)
+      {
+
+      srcptr = png_ptr->row_buf + 1;
+      dstptr = row;
+
+      unmask = ~mask;
+      len     = (png_ptr->width)&~7;
+      diff = (png_ptr->width)&7;
+      _asm {
+        movd    mm7, unmask   //load bit pattern
+        psubb   mm6,mm6       //zero mm6
+        punpcklbw mm7,mm7
+        punpcklwd mm7,mm7
+        punpckldq mm7,mm7     //fill register with 8 masks
+
+        movq    mm0,mask0
+        movq    mm1,mask1
+        movq    mm2,mask2
+        movq    mm3,mask3
+        movq    mm4,mask4
+        movq    mm5,mask5
+
+        pand    mm0,mm7
+        pand    mm1,mm7
+        pand    mm2,mm7
+        pand    mm3,mm7
+        pand    mm4,mm7
+        pand    mm5,mm7
+
+        pcmpeqb mm0,mm6
+        pcmpeqb mm1,mm6
+        pcmpeqb mm2,mm6
+        pcmpeqb mm3,mm6
+        pcmpeqb mm4,mm6
+        pcmpeqb mm5,mm6
+
+        mov             ecx,len       //load length of line
+        mov             esi,srcptr    //load source
+        mov             ebx,dstptr    //load dest
+
+            cmp   ecx,0
+            jz    mainloop48end
+
+mainloop48:
+        movq    mm7,[esi]
+        pand    mm7,mm0
+        movq    mm6,mm0
+        pandn   mm6,[ebx]
+        por             mm7,mm6
+        movq    [ebx],mm7
+
+
+        movq    mm6,[esi+8]
+        pand    mm6,mm1
+        movq    mm7,mm1
+        pandn   mm7,[ebx+8]
+        por             mm6,mm7
+        movq    [ebx+8],mm6
+
+        movq    mm6,[esi+16]
+        pand    mm6,mm2
+        movq    mm7,mm2
+        pandn   mm7,[ebx+16]
+        por             mm6,mm7
+        movq    [ebx+16],mm6
+
+        movq    mm7,[esi+24]
+        pand    mm7,mm3
+        movq    mm6,mm3
+        pandn   mm6,[ebx+24]
+        por             mm7,mm6
+        movq    [ebx+24],mm7
+
+        movq    mm6,[esi+32]
+        pand    mm6,mm4
+        movq    mm7,mm4
+        pandn   mm7,[ebx+32]
+        por             mm6,mm7
+        movq    [ebx+32],mm6
+
+        movq    mm7,[esi+40]
+        pand    mm7,mm5
+        movq    mm6,mm5
+        pandn   mm6,[ebx+40]
+        por             mm7,mm6
+        movq    [ebx+40],mm7
+
+        add             esi,48   //inc by 32 bytes processed
+        add             ebx,48
+        sub             ecx,8    //dec by 8 pixels processed
+
+        ja              mainloop48
+mainloop48end:
+
+        mov             ecx,diff
+        cmp             ecx,0
+        jz              end48
+
+        mov             edx,mask
+        sal             edx,24   //make low byte the high byte
+
+secondloop48:
+        sal             edx,1    //move high bit to CF
+        jnc             skip48   //if CF = 0
+        mov             eax,[esi]
+        mov             [ebx],eax
+skip48:
+        add             esi,4
+        add             ebx,4
+
+        dec             ecx
+        jnz secondloop48
+
+end48:
+        emms
+        }
+        }
+        else /* mmx _not supported - Use modified C routine */
+        {
+          register unsigned int incr1, initial_val, final_val;
+          png_size_t pixel_bytes;
+          png_uint_32 i;
+          register int disp = png_pass_inc[png_ptr->pass];
+          int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+          pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+          srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+             pixel_bytes;
+          dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+          initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+          final_val = png_ptr->width*pixel_bytes;
+          incr1 = (disp)*pixel_bytes;
+          for (i = initial_val; i < final_val; i += incr1)
+          {
+          png_memcpy(dstptr, srcptr, pixel_bytes);
+          srcptr += incr1;
+          dstptr += incr1;
+          }
+        } /* end of else */
+      break;  // end 48 bpp
+      }
+  default:
+      {
+      png_bytep sptr;
+      png_bytep dp;
+      png_size_t pixel_bytes;
+      int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+      unsigned int i;
+      register int disp = png_pass_inc[png_ptr->pass];   // get the offset
+      register unsigned int incr1, initial_val, final_val;
+      pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+      sptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*pixel_bytes;
+      dp = row + offset_table[png_ptr->pass]*pixel_bytes;
+      initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+      final_val = png_ptr->width*pixel_bytes;
+      incr1 = (disp)*pixel_bytes;
+      for (i = initial_val; i < final_val; i += incr1)
+      {
+        png_memcpy(dp, sptr, pixel_bytes);
+        sptr += incr1;
+        dp += incr1;
+      }
+
+      break;
+      }
+    }
+  }
+}
+
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
+
+void
+png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
+   png_uint_32 transformations)
+{
+
+   png_debug(1,"in png_do_read_interlace\n");
+   if (mmx_supported==2)
+       mmx_supported=mmxsupport();
+
+   if (row != NULL && row_info != NULL)
+   {
+      png_uint_32 final_width;
+
+      final_width = row_info->width * png_pass_inc[pass];
+
+      switch (row_info->pixel_depth)
+      {
+   case 1:
+   {
+      png_bytep sp, dp;
+      int sshift, dshift;
+      int s_start, s_end, s_inc;
+      png_byte v;
+      png_uint_32 i;
+      int j;
+
+      sp = row + (png_size_t)((row_info->width - 1) >> 3);
+      dp = row + (png_size_t)((final_width - 1) >> 3);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+      if (transformations & PNG_PACKSWAP)
+      {
+    sshift = (int)((row_info->width + 7) & 7);
+    dshift = (int)((final_width + 7) & 7);
+    s_start = 7;
+    s_end = 0;
+    s_inc = -1;
+      }
+      else
+#endif
+      {
+    sshift = 7 - (int)((row_info->width + 7) & 7);
+    dshift = 7 - (int)((final_width + 7) & 7);
+    s_start = 0;
+    s_end = 7;
+    s_inc = 1;
+      }
+
+      for (i = row_info->width; i; i--)
+      {
+         v = (png_byte)((*sp >> sshift) & 0x1);
+         for (j = 0; j < png_pass_inc[pass]; j++)
+         {
+      *dp &= (png_byte)((0x7f7f >> (7 - dshift)) & 0xff);
+      *dp |= (png_byte)(v << dshift);
+      if (dshift == s_end)
+      {
+         dshift = s_start;
+         dp--;
+      }
+      else
+         dshift += s_inc;
+         }
+         if (sshift == s_end)
+         {
+      sshift = s_start;
+      sp--;
+         }
+         else
+      sshift += s_inc;
+      }
+      break;
+   }
+   case 2:
+   {
+      png_bytep sp, dp;
+      int sshift, dshift;
+      int s_start, s_end, s_inc;
+      png_uint_32 i;
+
+      sp = row + (png_size_t)((row_info->width - 1) >> 2);
+      dp = row + (png_size_t)((final_width - 1) >> 2);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+      if (transformations & PNG_PACKSWAP)
+      {
+         sshift = (png_size_t)(((row_info->width + 3) & 3) << 1);
+         dshift = (png_size_t)(((final_width + 3) & 3) << 1);
+         s_start = 6;
+         s_end = 0;
+         s_inc = -2;
+      }
+      else
+#endif
+      {
+         sshift = (png_size_t)((3 - ((row_info->width + 3) & 3)) << 1);
+         dshift = (png_size_t)((3 - ((final_width + 3) & 3)) << 1);
+         s_start = 0;
+         s_end = 6;
+         s_inc = 2;
+      }
+
+      for (i = row_info->width; i; i--)
+      {
+         png_byte v;
+         int j;
+
+         v = (png_byte)((*sp >> sshift) & 0x3);
+         for (j = 0; j < png_pass_inc[pass]; j++)
+         {
+      *dp &= (png_byte)((0x3f3f >> (6 - dshift)) & 0xff);
+      *dp |= (png_byte)(v << dshift);
+      if (dshift == s_end)
+      {
+         dshift = s_start;
+         dp--;
+      }
+      else
+         dshift += s_inc;
+         }
+         if (sshift == s_end)
+         {
+      sshift = s_start;
+      sp--;
+         }
+         else
+      sshift += s_inc;
+      }
+      break;
+   }
+   case 4:
+   {
+      png_bytep sp, dp;
+      int sshift, dshift;
+      int s_start, s_end, s_inc;
+      png_uint_32 i;
+
+      sp = row + (png_size_t)((row_info->width - 1) >> 1);
+      dp = row + (png_size_t)((final_width - 1) >> 1);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+      if (transformations & PNG_PACKSWAP)
+      {
+         sshift = (png_size_t)(((row_info->width + 1) & 1) << 2);
+         dshift = (png_size_t)(((final_width + 1) & 1) << 2);
+         s_start = 4;
+         s_end = 0;
+         s_inc = -4;
+      }
+      else
+#endif
+      {
+         sshift = (png_size_t)((1 - ((row_info->width + 1) & 1)) << 2);
+         dshift = (png_size_t)((1 - ((final_width + 1) & 1)) << 2);
+         s_start = 0;
+         s_end = 4;
+         s_inc = 4;
+      }
+
+      for (i = row_info->width; i; i--)
+      {
+         png_byte v;
+         int j;
+
+         v = (png_byte)((*sp >> sshift) & 0xf);
+         for (j = 0; j < png_pass_inc[pass]; j++)
+         {
+      *dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff);
+      *dp |= (png_byte)(v << dshift);
+      if (dshift == s_end)
+      {
+         dshift = s_start;
+         dp--;
+      }
+      else
+         dshift += s_inc;
+         }
+         if (sshift == s_end)
+         {
+      sshift = s_start;
+      sp--;
+         }
+         else
+      sshift += s_inc;
+      }
+      break;
+   }
+   default:         // This is the place where the routine is modified
+   {
+      __int64 const4 = 0x0000000000FFFFFF;
+      __int64 const5 = 0x000000FFFFFF0000;
+      __int64 const6 = 0x00000000000000FF;
+      //int mmx_supported = 1;
+
+      png_bytep sptr, dp;
+      png_uint_32 i;
+      png_size_t pixel_bytes;
+
+      int width = row_info->width;
+
+      pixel_bytes = (row_info->pixel_depth >> 3);
+
+      sptr = row + (row_info->width - 1) * pixel_bytes;
+      dp = row + (final_width - 1) * pixel_bytes;
+      // New code by Nirav Chhatrapati - Intel Corporation
+
+      if (mmx_supported) // If machine supports MMX technology use MMX routine
+      {
+      if (pixel_bytes == 3)
+      {
+        if ((pass == 0) || (pass == 1))
+        {
+          _asm
+          {
+            mov esi, sptr
+
+            mov edi, dp
+
+            mov ecx, width
+
+            sub edi, 21   // (png_pass_inc[pass] - 1)*pixel_bytes
+
+loop_pass0:
+
+            movd mm0, [esi]     ; X X X X X val2 val1 val0
+
+            pand mm0, const4    ; 0 0 0 0 0 val2 val1 val0
+
+            movq mm1, mm0       ; 0 0 0 0 0 val2 val1 val0
+
+            psllq mm0, 16       ; 0 0 0 val2 val1 val0 0 0
+
+            movq mm2, mm0       ; 0 0 0 val2 val1 val0 0 0
+
+            psllq mm0, 24       ; val2 val1 val0 0 0 0 0 0
+
+            psrlq mm1, 8        ; 0 0 0 0 0 0 val2 val1
+
+            por mm0, mm2        ; val2 val1 val0 val2 val1 val0 0 0
+
+            por mm0, mm1        ; val2 val1 val0 val2 val1 val0 val2 val1
+
+            movq mm3, mm0       ; val2 val1 val0 val2 val1 val0 val2 val1
+
+            psllq mm0, 16       ; val0 val2 val1 val0 val2 val1 0 0
+
+            movq mm4, mm3       ; val2 val1 val0 val2 val1 val0 val2 val1
+
+            punpckhdq mm3, mm0  ; val0 val2 val1 val0 val2 val1 val0 val2
+
+            movq [edi+16] , mm4
+
+            psrlq mm0, 32       ; 0 0 0 0 val0 val2 val1 val0
+
+            movq [edi+8] , mm3
+
+            punpckldq mm0, mm4  ; val1 val0 val2 val1 val0 val2 val1 val0
+
+            sub esi, 3
+
+            movq [edi], mm0
+
+            sub edi, 24
+
+            //sub esi, 3
+
+            dec ecx
+
+            jnz loop_pass0
+
+            EMMS
+          }
+
+        }
+
+        else if ((pass == 2) || (pass == 3))
+        {
+          _asm
+          {
+            mov esi, sptr
+
+            mov edi, dp
+
+            mov ecx, width
+
+            sub edi, 9   // (png_pass_inc[pass] - 1)*pixel_bytes
+
+loop_pass2:
+
+            movd mm0, [esi]     ; X X X X X val2 val1 val0
+
+            pand mm0, const4    ; 0 0 0 0 0 val2 val1 val0
+
+            movq mm1, mm0       ; 0 0 0 0 0 val2 val1 val0
+
+            psllq mm0, 16       ; 0 0 0 val2 val1 val0 0 0
+
+            movq mm2, mm0       ; 0 0 0 val2 val1 val0 0 0
+
+            psllq mm0, 24       ; val2 val1 val0 0 0 0 0 0
+
+            psrlq mm1, 8        ; 0 0 0 0 0 0 val2 val1
+
+            por mm0, mm2        ; val2 val1 val0 val2 val1 val0 0 0
+
+            por mm0, mm1        ; val2 val1 val0 val2 val1 val0 val2 val1
+
+            movq [edi+4], mm0   ; move to memory
+
+            psrlq mm0, 16       ; 0 0 val2 val1 val0 val2 val1 val0
+
+            movd [edi], mm0     ; move to memory
+
+            sub esi, 3
+
+            sub edi, 12
+
+            dec ecx
+
+            jnz loop_pass2
+
+            EMMS
+          }
+        }
+
+        else /*if ((pass == 4) || (pass == 5)) */
+        {
+
+          int width_mmx = ((width >> 1) << 1) - 8;
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+            mov esi, sptr
+
+            mov edi, dp
+
+            mov ecx, width_mmx
+
+            sub esi, 3
+
+            sub edi, 9
+
+loop_pass4:
+
+            movq mm0, [esi]     ; X X v2 v1 v0 v5 v4 v3
+
+            movq mm7, mm0       ; X X v2 v1 v0 v5 v4 v3
+
+            movq mm6, mm0       ; X X v2 v1 v0 v5 v4 v3
+
+            psllq mm0, 24       ; v1 v0 v5 v4 v3 0 0 0
+
+            pand mm7, const4    ; 0 0 0 0 0 v5 v4 v3
+
+            psrlq mm6, 24       ; 0 0 0 X X v2 v1 v0
+
+            por mm0, mm7        ; v1 v0 v5 v4 v3 v5 v4 v3
+
+            movq mm5, mm6       ; 0 0 0 X X v2 v1 v0
+
+            psllq mm6, 8        ; 0 0 X X v2 v1 v0 0
+
+            movq [edi], mm0     ; move quad to memory
+
+            psrlq mm5, 16       ; 0 0 0 0 0 X X v2
+
+            pand mm5, const6    ; 0 0 0 0 0 0 0 v2
+
+            por mm6, mm5        ; 0 0 X X v2 v1 v0 v2
+
+            movd [edi+8], mm6   ; move double to memory
+
+            sub esi, 6
+
+            sub edi, 12
+
+            sub ecx, 2
+
+            jnz loop_pass4
+
+            EMMS
+          }
+
+          sptr -= width_mmx*3;
+          dp -= width_mmx*6;
+          for (i = width; i; i--)
+          {
+            png_byte v[8];
+            int j;
+
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              png_memcpy(dp, v, pixel_bytes);
+              dp -= pixel_bytes;
+            }
+           sptr -= pixel_bytes;
+           }
+
+        }
+
+      }  /* end of pixel_bytes == 3 */
+
+      else if (pixel_bytes == 1)
+      {
+
+        if ((pass == 0) || (pass == 1))
+        {
+          int width_mmx = ((width >> 2) << 2);
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+
+            mov esi, sptr
+
+            mov edi, dp
+
+            mov ecx, width_mmx
+
+            sub edi, 31
+
+            sub esi, 3
+
+loop1_pass0:
+
+            movd mm0, [esi]     ; X X X X v0 v1 v2 v3
+
+            movq mm1, mm0       ; X X X X v0 v1 v2 v3
+
+            punpcklbw mm0, mm0  ; v0 v0 v1 v1 v2 v2 v3 v3
+
+            movq mm2, mm0       ; v0 v0 v1 v1 v2 v2 v3 v3
+
+            punpcklwd mm0, mm0  ; v2 v2 v2 v2 v3 v3 v3 v3
+
+            movq mm3, mm0       ; v2 v2 v2 v2 v3 v3 v3 v3
+
+            punpckldq mm0, mm0  ; v3 v3 v3 v3 v3 v3 v3 v3
+
+            punpckhdq mm3, mm3  ; v2 v2 v2 v2 v2 v2 v2 v2
+
+            movq [edi], mm0     ; move to memory v3
+
+            punpckhwd mm2, mm2  ; v0 v0 v0 v0 v1 v1 v1 v1
+
+            movq [edi+8], mm3   ; move to memory v2
+
+            movq mm4, mm2       ; v0 v0 v0 v0 v1 v1 v1 v1
+
+            punpckldq mm2, mm2  ; v1 v1 v1 v1 v1 v1 v1 v1
+
+            punpckhdq mm4, mm4  ; v0 v0 v0 v0 v0 v0 v0 v0
+
+            movq [edi+16], mm2  ; move to memory v1
+
+            movq [edi+24], mm4  ; move to memory v0
+
+            sub esi, 4
+
+            sub edi, 32
+
+            sub ecx, 4
+
+            jnz loop1_pass0
+
+            EMMS
+          }
+
+          sptr -= width_mmx;
+          dp -= width_mmx*8;
+          for (i = width; i; i--)
+          {
+            png_byte v[8];
+            int j;
+
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              png_memcpy(dp, v, pixel_bytes);
+              dp -= pixel_bytes;
+            }
+           sptr -= pixel_bytes;
+          }
+
+        }
+
+
+        else if ((pass == 2) || (pass == 3))
+        {
+          int width_mmx = ((width >> 2) << 2);
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+
+            mov esi, sptr
+
+            mov edi, dp
+
+            mov ecx, width_mmx
+
+            sub edi, 15
+
+            sub esi, 3
+
+loop1_pass2:
+
+            movd mm0, [esi]     ; X X X X v0 v1 v2 v3
+
+            punpcklbw mm0, mm0  ; v0 v0 v1 v1 v2 v2 v3 v3
+
+            movq mm1, mm0       ; v0 v0 v1 v1 v2 v2 v3 v3
+
+            punpcklwd mm0, mm0  ; v2 v2 v2 v2 v3 v3 v3 v3
+
+            punpckhwd mm1, mm1  ; v0 v0 v0 v0 v1 v1 v1 v1
+
+            movq [edi], mm0     ; move to memory v2 and v3
+
+            sub esi, 4
+
+            movq [edi+8], mm1   ; move to memory v1     and v0
+
+            sub edi, 16
+
+            sub ecx, 4
+
+            jnz loop1_pass2
+
+            EMMS
+          }
+
+          sptr -= width_mmx;
+          dp -= width_mmx*4;
+          for (i = width; i; i--)
+          {
+            png_byte v[8];
+            int j;
+
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              png_memcpy(dp, v, pixel_bytes);
+              dp -= pixel_bytes;
+            }
+           sptr -= pixel_bytes;
+          }
+
+        }
+
+        else //if ((pass == 4) || (pass == 5))
+        {
+          int width_mmx = ((width >> 3) << 3);
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+
+            mov esi, sptr
+            mov edi, dp
+            mov ecx, width_mmx
+            sub edi, 15
+            sub esi, 7
+
+loop1_pass4:
+
+            movq mm0, [esi]     ; v0 v1 v2 v3 v4 v5 v6 v7
+            movq mm1, mm0       ; v0 v1 v2 v3 v4 v5 v6 v7
+            punpcklbw mm0, mm0  ; v4 v4 v5 v5 v6 v6 v7 v7
+            //movq mm1, mm0     ; v0 v0 v1 v1 v2 v2 v3 v3
+            punpckhbw mm1, mm1  ;v0 v0 v1 v1 v2 v2 v3 v3
+            movq [edi+8], mm1   ; move to memory v0 v1 v2 and v3
+            sub esi, 8
+            movq [edi], mm0     ; move to memory v4 v5 v6 and v7
+            //sub esi, 4
+            sub edi, 16
+            sub ecx, 8
+            jnz loop1_pass4
+
+            EMMS
+          }
+
+          sptr -= width_mmx;
+          dp -= width_mmx*2;
+          for (i = width; i; i--)
+          {
+            png_byte v[8];
+            int j;
+
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              png_memcpy(dp, v, pixel_bytes);
+              dp -= pixel_bytes;
+            }
+           sptr -= pixel_bytes;
+          }
+
+        }
+
+      }       /* end of pixel_bytes == 1 */
+
+      else if (pixel_bytes == 2)
+      {
+
+        if ((pass == 0) || (pass == 1))
+        {
+          int width_mmx = ((width >> 1) << 1);
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+            mov esi, sptr
+            mov edi, dp
+            mov ecx, width_mmx
+            sub esi, 2
+            sub edi, 30
+
+loop2_pass0:
+            movd mm0, [esi]        ; X X X X v1 v0 v3 v2
+            punpcklwd mm0, mm0     ; v1 v0 v1 v0 v3 v2 v3 v2
+            movq mm1, mm0          ; v1 v0 v1 v0 v3 v2 v3 v2
+            punpckldq mm0, mm0     ; v3 v2 v3 v2 v3 v2 v3 v2
+            punpckhdq mm1, mm1     ; v1 v0 v1 v0 v1 v0 v1 v0
+            movq [edi], mm0
+            movq [edi + 8], mm0
+            movq [edi + 16], mm1
+            movq [edi + 24], mm1
+            sub esi, 4
+            sub edi, 32
+            sub ecx, 2
+            jnz loop2_pass0
+
+            EMMS
+          }
+
+          sptr -= (width_mmx*2 + 2);
+          dp -= (width_mmx*16 + 2);
+
+          for (i = width; i; i--)
+          {
+
+            png_byte v[8];
+            int j;
+            sptr -= pixel_bytes;
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              dp -= pixel_bytes;
+              png_memcpy(dp, v, pixel_bytes);
+              //dp -= pixel_bytes;
+            }
+            //sptr -= pixel_bytes;
+          }
+        }
+
+        else if ((pass == 2) || (pass == 3))
+        {
+          int width_mmx = ((width >> 1) << 1) ;
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+            mov esi, sptr
+            mov edi, dp
+            mov ecx, width_mmx
+            sub esi, 2
+            sub edi, 14
+
+loop2_pass2:
+            movd mm0, [esi]        ; X X X X v1 v0 v3 v2
+            punpcklwd mm0, mm0     ; v1 v0 v1 v0 v3 v2 v3 v2
+            movq mm1, mm0          ; v1 v0 v1 v0 v3 v2 v3 v2
+            punpckldq mm0, mm0     ; v3 v2 v3 v2 v3 v2 v3 v2
+            punpckhdq mm1, mm1     ; v1 v0 v1 v0 v1 v0 v1 v0
+            movq [edi], mm0
+            sub esi, 4
+            movq [edi + 8], mm1
+            //sub esi, 4
+            sub edi, 16
+            sub ecx, 2
+            jnz loop2_pass2
+
+            EMMS
+          }
+
+          sptr -= (width_mmx*2 + 2);
+          dp -= (width_mmx*8 + 2);
+
+          for (i = width; i; i--)
+          {
+
+            png_byte v[8];
+            int j;
+            sptr -= pixel_bytes;
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              dp -= pixel_bytes;
+              png_memcpy(dp, v, pixel_bytes);
+              //dp -= pixel_bytes;
+            }
+            //sptr -= pixel_bytes;
+          }
+        }
+
+        else // pass == 4 or 5
+        {
+          int width_mmx = ((width >> 1) << 1) ;
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+            mov esi, sptr
+            mov edi, dp
+            mov ecx, width_mmx
+            sub esi, 2
+            sub edi, 6
+
+loop2_pass4:
+            movd mm0, [esi]        ; X X X X v1 v0 v3 v2
+            punpcklwd mm0, mm0     ; v1 v0 v1 v0 v3 v2 v3 v2
+            sub esi, 4
+            movq [edi], mm0
+            sub edi, 8
+            sub ecx, 2
+            jnz loop2_pass4
+
+            EMMS
+          }
+
+          sptr -= (width_mmx*2 + 2);
+          dp -= (width_mmx*4 + 2);
+
+          for (i = width; i; i--)
+          {
+
+            png_byte v[8];
+            int j;
+            sptr -= pixel_bytes;
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              dp -= pixel_bytes;
+              png_memcpy(dp, v, pixel_bytes);
+              //dp -= pixel_bytes;
+            }
+            //sptr -= pixel_bytes;
+          }
+        }
+
+      } /* end of pixel_bytes == 2 */
+
+      else if (pixel_bytes == 4)
+      {
+        if ((pass == 0) || (pass == 1))
+        {
+          int width_mmx = ((width >> 1) << 1) ;
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+            mov esi, sptr
+            mov edi, dp
+            mov ecx, width_mmx
+            sub esi, 4
+            sub edi, 60
+
+loop4_pass0:
+            movq mm0, [esi]        ; v3 v2 v1 v0 v7 v6 v5 v4
+            movq mm1, mm0          ; v3 v2 v1 v0 v7 v6 v5 v4
+            punpckldq mm0, mm0     ; v7 v6 v5 v4 v7 v6 v5 v4
+            punpckhdq mm1, mm1     ; v3 v2 v1 v0 v3 v2 v1 v0
+            movq [edi], mm0
+            movq [edi + 8], mm0
+            movq [edi + 16], mm0
+            movq [edi + 24], mm0
+            movq [edi+32], mm1
+            movq [edi + 40], mm1
+            movq [edi+ 48], mm1
+            sub esi, 8
+            movq [edi + 56], mm1
+            sub edi, 64
+            sub ecx, 2
+            jnz loop4_pass0
+
+            EMMS
+          }
+
+          sptr -= (width_mmx*4 + 4);
+          dp -= (width_mmx*32 + 4);
+
+          for (i = width; i; i--)
+          {
+
+            png_byte v[8];
+            int j;
+            sptr -= pixel_bytes;
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              dp -= pixel_bytes;
+              png_memcpy(dp, v, pixel_bytes);
+              //dp -= pixel_bytes;
+            }
+            //sptr -= pixel_bytes;
+          }
+        }
+
+        else if ((pass == 2) || (pass == 3))
+        {
+          int width_mmx = ((width >> 1) << 1) ;
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+            mov esi, sptr
+            mov edi, dp
+            mov ecx, width_mmx
+            sub esi, 4
+            sub edi, 28
+
+loop4_pass2:
+            movq mm0, [esi]      ; v3 v2 v1 v0 v7 v6 v5 v4
+            movq mm1, mm0        ; v3 v2 v1 v0 v7 v6 v5 v4
+            punpckldq mm0, mm0   ; v7 v6 v5 v4 v7 v6 v5 v4
+            punpckhdq mm1, mm1   ; v3 v2 v1 v0 v3 v2 v1 v0
+            movq [edi], mm0
+            movq [edi + 8], mm0
+            movq [edi+16], mm1
+            movq [edi + 24], mm1
+            sub esi, 8
+            sub edi, 32
+            sub ecx, 2
+            jnz loop4_pass2
+
+            EMMS
+          }
+
+          sptr -= (width_mmx*4 + 4);
+          dp -= (width_mmx*16 + 4);
+
+          for (i = width; i; i--)
+          {
+
+            png_byte v[8];
+            int j;
+            sptr -= pixel_bytes;
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              dp -= pixel_bytes;
+              png_memcpy(dp, v, pixel_bytes);
+              //dp -= pixel_bytes;
+            }
+            //sptr -= pixel_bytes;
+          }
+        }
+
+        else // pass == 4 or 5
+        {
+          int width_mmx = ((width >> 1) << 1) ;
+          width -= width_mmx;
+               if(width_mmx)
+          _asm
+          {
+            mov esi, sptr
+            mov edi, dp
+            mov ecx, width_mmx
+            sub esi, 4
+            sub edi, 12
+
+loop4_pass4:
+            movq mm0, [esi]      ; v3 v2 v1 v0 v7 v6 v5 v4
+            movq mm1, mm0        ; v3 v2 v1 v0 v7 v6 v5 v4
+            punpckldq mm0, mm0   ; v7 v6 v5 v4 v7 v6 v5 v4
+            punpckhdq mm1, mm1   ; v3 v2 v1 v0 v3 v2 v1 v0
+            movq [edi], mm0
+            sub esi, 8
+            movq [edi + 8], mm1
+            sub edi, 16
+            sub ecx, 2
+            jnz loop4_pass4
+
+            EMMS
+          }
+
+          sptr -= (width_mmx*4 + 4);
+          dp -= (width_mmx*8 + 4);
+
+          for (i = width; i; i--)
+          {
+
+            png_byte v[8];
+            int j;
+            sptr -= pixel_bytes;
+            png_memcpy(v, sptr, pixel_bytes);
+            for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+              dp -= pixel_bytes;
+              png_memcpy(dp, v, pixel_bytes);
+              //dp -= pixel_bytes;
+            }
+            //sptr -= pixel_bytes;
+          }
+        }
+
+      } /* end of pixel_bytes == 4 */
+
+      else if (pixel_bytes == 6)
+      {
+        for (i = row_info->width; i; i--)
+        {
+
+          png_byte v[8];
+          int j;
+          png_memcpy(v, sptr, pixel_bytes);
+          for (j = 0; j < png_pass_inc[pass]; j++)
+          {
+            png_memcpy(dp, v, pixel_bytes);
+            dp -= pixel_bytes;
+          }
+          sptr -= pixel_bytes;
+        }
+      } /* end of pixel_bytes == 6 */
+
+      else
+      {
+      for (i = row_info->width; i; i--)
+        {
+
+          png_byte v[8];
+          int j;
+          png_memcpy(v, sptr, pixel_bytes);
+          for (j = 0; j < png_pass_inc[pass]; j++)
+          {
+            png_memcpy(dp, v, pixel_bytes);
+            dp -= pixel_bytes;
+          }
+          sptr-= pixel_bytes;
+        }
+      }
+      }       /* end of mmx_supported */
+
+      else   /* MMX not supported */
+      /* use modified C code - takes advantage of inlining of memcpy for
+         a constant */
+      {
+        if (pixel_bytes == 1)
+        {
+        for (i = row_info->width; i; i--)
+          {
+          png_byte v[8];
+          int j;
+
+          png_memcpy(v, sptr, pixel_bytes);
+          for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+            png_memcpy(dp, v, pixel_bytes);
+            dp -= pixel_bytes;
+            }
+          sptr -= pixel_bytes;
+          }
+        }
+        else if (pixel_bytes == 3)
+        {
+        for (i = row_info->width; i; i--)
+        {
+          png_byte v[8];
+          int j;
+      png_memcpy(v, sptr, pixel_bytes);
+         for (j = 0; j < png_pass_inc[pass]; j++)
+            {
+            png_memcpy(dp, v, pixel_bytes);
+            dp -= pixel_bytes;
+            }
+          sptr -= pixel_bytes;
+          }
+        }
+        else if (pixel_bytes == 2)
+        {
+        for (i = row_info->width; i; i--)
+          {
+          png_byte v[8];
+          int j;
+      png_memcpy(v, sptr, pixel_bytes);
+        for (j = 0; j < png_pass_inc[pass]; j++)
+             {
+            png_memcpy(dp, v, pixel_bytes);
+            dp -= pixel_bytes;
+            }
+          sptr -= pixel_bytes;
+          }
+        }
+        else if (pixel_bytes == 4)
+        {
+        for (i = row_info->width; i; i--)
+          {
+          png_byte v[8];
+          int j;
+      png_memcpy(v, sptr, pixel_bytes);
+        for (j = 0; j < png_pass_inc[pass]; j++)
+             {
+            png_memcpy(dp, v, pixel_bytes);
+            dp -= pixel_bytes;
+            }
+          sptr -= pixel_bytes;
+          }
+        }
+        else if (pixel_bytes == 6)
+        {
+        for (i = row_info->width; i; i--)
+          {
+          png_byte v[8];
+          int j;
+      png_memcpy(v, sptr, pixel_bytes);
+        for (j = 0; j < png_pass_inc[pass]; j++)
+             {
+            png_memcpy(dp, v, pixel_bytes);
+            dp -= pixel_bytes;
+            }
+          sptr -= pixel_bytes;
+          }
+        }
+        else
+        {
+        for (i = row_info->width; i; i--)
+          {
+          png_byte v[8];
+          int j;
+           png_memcpy(v, sptr, pixel_bytes);
+         for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+              png_memcpy(dp, v, pixel_bytes);
+            dp -= pixel_bytes;
+            }
+          sptr -= pixel_bytes;
+          }
+        }
+
+      } /* end of MMX not supported */
+      break;
+   }
+      }
+    row_info->width = final_width;
+      row_info->rowbytes = ((final_width *
+   (png_uint_32)row_info->pixel_depth + 7) >> 3);
+   }
+}
+
+#endif
+
+
+
+// These variables are utilized in the functions below.  They are declared
+// globally here to ensure alignment on 8-byte boundaries.
+union uAll {
+   __int64 use;
+   double  align;
+}  LBCarryMask = {0x0101010101010101}, HBClearMask = {0x7f7f7f7f7f7f7f7f},
+   ActiveMask, ActiveMask2, ActiveMaskEnd, ShiftBpp, ShiftRem;
+
+// Optimized code for PNG Average filter decoder
+void
+png_read_filter_row_mmx_avg(png_row_infop row_info, png_bytep row
+                            , png_bytep prev_row)
+{
+      int bpp;
+      png_uint_32 FullLength;
+      png_uint_32 MMXLength;
+      //png_uint_32 len;
+      int diff;
+      bpp = (row_info->pixel_depth + 7) >> 3; // Get # bytes per pixel
+    FullLength  = row_info->rowbytes; // # of bytes to filter
+      _asm {
+         // Init address pointers and offset
+         mov edi, row          // edi ==> Avg(x)
+         xor ebx, ebx          // ebx ==> x
+         mov edx, edi
+   mov esi, prev_row           // esi ==> Prior(x)
+         sub edx, bpp          // edx ==> Raw(x-bpp)
+
+         xor eax, eax
+         // Compute the Raw value for the first bpp bytes
+         //    Raw(x) = Avg(x) + (Prior(x)/2)
+davgrlp:
+         mov al, [esi + ebx]   // Load al with Prior(x)
+   inc ebx
+         shr al, 1             // divide by 2
+         add al, [edi+ebx-1]   // Add Avg(x); -1 to offset inc ebx
+         cmp ebx, bpp
+   mov [edi+ebx-1], al    // Write back Raw(x);
+                          // mov does not affect flags; -1 to offset inc ebx
+         jb davgrlp
+         // get # of bytes to alignment
+         mov diff, edi         // take start of row
+         add diff, ebx         // add bpp
+         add diff, 0xf         // add 7 + 8 to incr past alignment boundary
+         and diff, 0xfffffff8  // mask to alignment boundary
+         sub diff, edi         // subtract from start ==> value ebx at alignment
+         jz davggo
+         // fix alignment
+         // Compute the Raw value for the bytes upto the alignment boundary
+         //    Raw(x) = Avg(x) + ((Raw(x-bpp) + Prior(x))/2)
+         xor ecx, ecx
+davglp1:
+         xor eax, eax
+   mov cl, [esi + ebx]        // load cl with Prior(x)
+         mov al, [edx + ebx]  // load al with Raw(x-bpp)
+         add ax, cx
+   inc ebx
+         shr ax, 1            // divide by 2
+         add al, [edi+ebx-1]  // Add Avg(x); -1 to offset inc ebx
+   cmp ebx, diff              // Check if at alignment boundary
+   mov [edi+ebx-1], al        // Write back Raw(x);
+                            // mov does not affect flags; -1 to offset inc ebx
+   jb davglp1               // Repeat until at alignment boundary
+davggo:
+   mov eax, FullLength
+         mov ecx, eax
+         sub eax, ebx          // subtract alignment fix
+         and eax, 0x00000007   // calc bytes over mult of 8
+         sub ecx, eax          // drop over bytes from original length
+         mov MMXLength, ecx
+      } // end _asm block
+      // Now do the math for the rest of the row
+      switch ( bpp )
+      {
+      case 3:
+      {
+         ActiveMask.use  = 0x0000000000ffffff;
+         ShiftBpp.use = 24;    // == 3 * 8
+         ShiftRem.use = 40;    // == 64 - 24
+         _asm {
+            // Re-init address pointers and offset
+            movq mm7, ActiveMask
+            mov ebx, diff      // ebx ==> x = offset to alignment boundary
+            movq mm5, LBCarryMask
+            mov edi, row       // edi ==> Avg(x)
+            movq mm4, HBClearMask
+      mov esi, prev_row        // esi ==> Prior(x)
+            // PRIME the pump (load the first Raw(x-bpp) data set
+      movq mm2, [edi + ebx - 8]  // Load previous aligned 8 bytes
+                               // (we correct position in loop below)
+davg3lp:
+      movq mm0, [edi + ebx]      // Load mm0 with Avg(x)
+            // Add (Prev_row/2) to Average
+            movq mm3, mm5
+            psrlq mm2, ShiftRem      // Correct position Raw(x-bpp) data
+      movq mm1, [esi + ebx]    // Load mm1 with Prior(x)
+            movq mm6, mm7
+            pand mm3, mm1      // get lsb for each prev_row byte
+            psrlq mm1, 1       // divide prev_row bytes by 2
+            pand  mm1, mm4     // clear invalid bit 7 of each byte
+      paddb mm0, mm1           // add (Prev_row/2) to Avg for each byte
+            // Add 1st active group (Raw(x-bpp)/2) to Average with LBCarry
+            movq mm1, mm3      // now use mm1 for getting LBCarrys
+            pand mm1, mm2      // get LBCarrys for each byte where both
+                               // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1       // divide raw bytes by 2
+            pand  mm2, mm4     // clear invalid bit 7 of each byte
+            paddb mm2, mm1     // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6      // Leave only Active Group 1 bytes to add to Avg
+      paddb mm0, mm2      // add (Raw/2) + LBCarrys to Avg for each Active byte
+            // Add 2nd active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp  // shift the mm6 mask to cover bytes 3-5
+            movq mm2, mm0        // mov updated Raws to mm2
+            psllq mm2, ShiftBpp  // shift data to position correctly
+            movq mm1, mm3        // now use mm1 for getting LBCarrys
+            pand mm1, mm2        // get LBCarrys for each byte where both
+                                 // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1         // divide raw bytes by 2
+            pand  mm2, mm4       // clear invalid bit 7 of each byte
+            paddb mm2, mm1       // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6        // Leave only Active Group 2 bytes to add to Avg
+      paddb mm0, mm2     // add (Raw/2) + LBCarrys to Avg for each Active byte
+
+            // Add 3rd active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp  // shift the mm6 mask to cover the last two bytes
+            movq mm2, mm0        // mov updated Raws to mm2
+            psllq mm2, ShiftBpp  // shift data to position correctly
+                                 // Data only needs to be shifted once here to
+                                 // get the correct x-bpp offset.
+            movq mm1, mm3        // now use mm1 for getting LBCarrys
+            pand mm1, mm2        // get LBCarrys for each byte where both
+                                 // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1         // divide raw bytes by 2
+            pand  mm2, mm4       // clear invalid bit 7 of each byte
+            paddb mm2, mm1       // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6        // Leave only Active Group 2 bytes to add to Avg
+      add ebx, 8
+      paddb mm0, mm2     // add (Raw/2) + LBCarrys to Avg for each Active byte
+
+            // Now ready to write back to memory
+      movq [edi + ebx - 8], mm0
+            // Move updated Raw(x) to use as Raw(x-bpp) for next loop
+      cmp ebx, MMXLength
+            movq mm2, mm0     // mov updated Raw(x) to mm2
+      jb davg3lp
+   } // end _asm block
+      }
+      break;
+      case 6:
+      case 4:
+      case 7:
+      case 5:
+      {
+         ActiveMask.use  = 0xffffffffffffffff;  // use shift below to clear
+                                               // appropriate inactive bytes
+         ShiftBpp.use = bpp << 3;
+         ShiftRem.use = 64 - ShiftBpp.use;
+   _asm {
+            movq mm4, HBClearMask
+            // Re-init address pointers and offset
+            mov ebx, diff       // ebx ==> x = offset to alignment boundary
+            // Load ActiveMask and clear all bytes except for 1st active group
+            movq mm7, ActiveMask
+            mov edi, row                  // edi ==> Avg(x)
+            psrlq mm7, ShiftRem
+      mov esi, prev_row             // esi ==> Prior(x)
+            movq mm6, mm7
+            movq mm5, LBCarryMask
+            psllq mm6, ShiftBpp    // Create mask for 2nd active group
+            // PRIME the pump (load the first Raw(x-bpp) data set
+      movq mm2, [edi + ebx - 8]  // Load previous aligned 8 bytes
+                                 // (we correct position in loop below)
+davg4lp:
+      movq mm0, [edi + ebx]
+            psrlq mm2, ShiftRem  // shift data to position correctly
+      movq mm1, [esi + ebx]
+            // Add (Prev_row/2) to Average
+            movq mm3, mm5
+            pand mm3, mm1        // get lsb for each prev_row byte
+            psrlq mm1, 1         // divide prev_row bytes by 2
+            pand  mm1, mm4       // clear invalid bit 7 of each byte
+      paddb mm0, mm1             // add (Prev_row/2) to Avg for each byte
+            // Add 1st active group (Raw(x-bpp)/2) to Average with LBCarry
+            movq mm1, mm3        // now use mm1 for getting LBCarrys
+            pand mm1, mm2        // get LBCarrys for each byte where both
+                                 // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1         // divide raw bytes by 2
+            pand  mm2, mm4       // clear invalid bit 7 of each byte
+            paddb mm2, mm1       // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm7        // Leave only Active Group 1 bytes to add to Avg
+      paddb mm0, mm2    // add (Raw/2) + LBCarrys to Avg for each Active byte
+            // Add 2nd active group (Raw(x-bpp)/2) to Average with LBCarry
+            movq mm2, mm0        // mov updated Raws to mm2
+            psllq mm2, ShiftBpp  // shift data to position correctly
+      add ebx, 8
+            movq mm1, mm3        // now use mm1 for getting LBCarrys
+            pand mm1, mm2        // get LBCarrys for each byte where both
+                                 // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1         // divide raw bytes by 2
+            pand  mm2, mm4       // clear invalid bit 7 of each byte
+            paddb mm2, mm1       // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6        // Leave only Active Group 2 bytes to add to Avg
+      paddb mm0, mm2    // add (Raw/2) + LBCarrys to Avg for each Active byte
+      cmp ebx, MMXLength
+            // Now ready to write back to memory
+      movq [edi + ebx - 8], mm0
+            // Prep Raw(x-bpp) for next loop
+            movq mm2, mm0        // mov updated Raws to mm2
+      jb davg4lp
+   } // end _asm block
+      }
+      break;
+      case 2:
+      {
+         ActiveMask.use  = 0x000000000000ffff;
+         ShiftBpp.use = 24;      // == 3 * 8
+         ShiftRem.use = 40;      // == 64 - 24
+   _asm {
+            // Load ActiveMask
+            movq mm7, ActiveMask
+            // Re-init address pointers and offset
+            mov ebx, diff        // ebx ==> x = offset to alignment boundary
+            movq mm5, LBCarryMask
+            mov edi, row         // edi ==> Avg(x)
+            movq mm4, HBClearMask
+      mov esi, prev_row          // esi ==> Prior(x)
+            // PRIME the pump (load the first Raw(x-bpp) data set
+      movq mm2, [edi + ebx - 8]  // Load previous aligned 8 bytes
+                                 // (we correct position in loop below)
+davg2lp:
+      movq mm0, [edi + ebx]
+            psllq mm2, ShiftRem  // shift data to position correctly
+      movq mm1, [esi + ebx]
+            // Add (Prev_row/2) to Average
+            movq mm3, mm5
+            pand mm3, mm1        // get lsb for each prev_row byte
+            psrlq mm1, 1         // divide prev_row bytes by 2
+            pand  mm1, mm4       // clear invalid bit 7 of each byte
+            movq mm6, mm7
+      paddb mm0, mm1             // add (Prev_row/2) to Avg for each byte
+            // Add 1st active group (Raw(x-bpp)/2) to Average with LBCarry
+            movq mm1, mm3        // now use mm1 for getting LBCarrys
+            pand mm1, mm2        // get LBCarrys for each byte where both
+                                 // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1         // divide raw bytes by 2
+            pand  mm2, mm4       // clear invalid bit 7 of each byte
+            paddb mm2, mm1       // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6        // Leave only Active Group 1 bytes to add to Avg
+      paddb mm0, mm2    // add (Raw/2) + LBCarrys to Avg for each Active byte
+            // Add 2nd active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp  // shift the mm6 mask to cover bytes 2 & 3
+            movq mm2, mm0        // mov updated Raws to mm2
+            psllq mm2, ShiftBpp  // shift data to position correctly
+            movq mm1, mm3        // now use mm1 for getting LBCarrys
+            pand mm1, mm2        // get LBCarrys for each byte where both
+                                 // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1         // divide raw bytes by 2
+            pand  mm2, mm4       // clear invalid bit 7 of each byte
+            paddb mm2, mm1       // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6        // Leave only Active Group 2 bytes to add to Avg
+      paddb mm0, mm2    // add (Raw/2) + LBCarrys to Avg for each Active byte
+
+            // Add rdd active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp  // shift the mm6 mask to cover bytes 4 & 5
+            movq mm2, mm0        // mov updated Raws to mm2
+            psllq mm2, ShiftBpp  // shift data to position correctly
+                                 // Data only needs to be shifted once here to
+                                 // get the correct x-bpp offset.
+            movq mm1, mm3        // now use mm1 for getting LBCarrys
+            pand mm1, mm2        // get LBCarrys for each byte where both
+                                 // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1         // divide raw bytes by 2
+            pand  mm2, mm4       // clear invalid bit 7 of each byte
+            paddb mm2, mm1       // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6        // Leave only Active Group 2 bytes to add to Avg
+      paddb mm0, mm2    // add (Raw/2) + LBCarrys to Avg for each Active byte
+
+            // Add 4th active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp  // shift the mm6 mask to cover bytes 6 & 7
+            movq mm2, mm0        // mov updated Raws to mm2
+            psllq mm2, ShiftBpp  // shift data to position correctly
+                                 // Data only needs to be shifted once here to
+                                 // get the correct x-bpp offset.
+            add ebx, 8
+            movq mm1, mm3        // now use mm1 for getting LBCarrys
+            pand mm1, mm2        // get LBCarrys for each byte where both
+                                 // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1         // divide raw bytes by 2
+            pand  mm2, mm4       // clear invalid bit 7 of each byte
+            paddb mm2, mm1       // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6        // Leave only Active Group 2 bytes to add to Avg
+      paddb mm0, mm2      // add (Raw/2) + LBCarrys to Avg for each Active byte
+
+      cmp ebx, MMXLength
+            // Now ready to write back to memory
+      movq [edi + ebx - 8], mm0
+            // Prep Raw(x-bpp) for next loop
+            movq mm2, mm0        // mov updated Raws to mm2
+      jb davg2lp
+  } // end _asm block
+      }
+      break;
+      case 1:                    // bpp == 1
+      {
+         _asm {
+            // Re-init address pointers and offset
+            mov ebx, diff        // ebx ==> x = offset to alignment boundary
+            mov edi, row         // edi ==> Avg(x)
+            cmp ebx, FullLength  // Test if offset at end of array
+      jnb davg1end
+            // Do Paeth decode for remaining bytes
+        mov esi, prev_row        // esi ==> Prior(x)
+            mov edx, edi
+            xor ecx, ecx         // zero ecx before using cl & cx in loop below
+            sub edx, bpp         // edx ==> Raw(x-bpp)
+davg1lp:
+            // Raw(x) = Avg(x) + ((Raw(x-bpp) + Prior(x))/2)
+            xor eax, eax
+      mov cl, [esi + ebx]        // load cl with Prior(x)
+            mov al, [edx + ebx]  // load al with Raw(x-bpp)
+            add ax, cx
+      inc ebx
+            shr ax, 1            // divide by 2
+            add al, [edi+ebx-1]  // Add Avg(x); -1 to offset inc ebx
+      cmp ebx, FullLength        // Check if at end of array
+      mov [edi+ebx-1], al        // Write back Raw(x);
+                         // mov does not affect flags; -1 to offset inc ebx
+      jb davg1lp
+davg1end:
+   } // end _asm block
+      }
+      return;
+
+      case 8:             // bpp == 8
+      {
+   _asm {
+            // Re-init address pointers and offset
+            mov ebx, diff           // ebx ==> x = offset to alignment boundary
+            movq mm5, LBCarryMask
+            mov edi, row            // edi ==> Avg(x)
+            movq mm4, HBClearMask
+      mov esi, prev_row             // esi ==> Prior(x)
+            // PRIME the pump (load the first Raw(x-bpp) data set
+      movq mm2, [edi + ebx - 8]  // Load previous aligned 8 bytes
+                                // (NO NEED to correct position in loop below)
+davg8lp:
+      movq mm0, [edi + ebx]
+            movq mm3, mm5
+      movq mm1, [esi + ebx]
+      add ebx, 8
+            pand mm3, mm1       // get lsb for each prev_row byte
+            psrlq mm1, 1        // divide prev_row bytes by 2
+            pand mm3, mm2       // get LBCarrys for each byte where both
+                                // lsb's were == 1
+            psrlq mm2, 1        // divide raw bytes by 2
+            pand  mm1, mm4      // clear invalid bit 7 of each byte
+            paddb mm0, mm3      // add LBCarrys to Avg for each byte
+            pand  mm2, mm4      // clear invalid bit 7 of each byte
+            paddb mm0, mm1      // add (Prev_row/2) to Avg for each byte
+      paddb mm0, mm2            // add (Raw/2) to Avg for each byte
+      cmp ebx, MMXLength
+      movq [edi + ebx - 8], mm0
+            movq mm2, mm0       // reuse as Raw(x-bpp)
+      jb davg8lp
+  } // end _asm block
+      }
+      break;
+      default:                  // bpp greater than 8
+      {
+  _asm {
+            movq mm5, LBCarryMask
+            // Re-init address pointers and offset
+            mov ebx, diff       // ebx ==> x = offset to alignment boundary
+            mov edi, row        // edi ==> Avg(x)
+            movq mm4, HBClearMask
+            mov edx, edi
+      mov esi, prev_row         // esi ==> Prior(x)
+            sub edx, bpp        // edx ==> Raw(x-bpp)
+davgAlp:
+      movq mm0, [edi + ebx]
+            movq mm3, mm5
+      movq mm1, [esi + ebx]
+            pand mm3, mm1       // get lsb for each prev_row byte
+      movq mm2, [edx + ebx]
+            psrlq mm1, 1        // divide prev_row bytes by 2
+            pand mm3, mm2       // get LBCarrys for each byte where both
+                                // lsb's were == 1
+            psrlq mm2, 1        // divide raw bytes by 2
+            pand  mm1, mm4      // clear invalid bit 7 of each byte
+            paddb mm0, mm3      // add LBCarrys to Avg for each byte
+            pand  mm2, mm4      // clear invalid bit 7 of each byte
+            paddb mm0, mm1      // add (Prev_row/2) to Avg for each byte
+      add ebx, 8
+      paddb mm0, mm2             // add (Raw/2) to Avg for each byte
+      cmp ebx, MMXLength
+      movq [edi + ebx - 8], mm0
+      jb davgAlp
+  } // end _asm block
+      }
+      break;
+      }                         // end switch ( bpp )
+
+      _asm {
+         // MMX acceleration complete now do clean-up
+         // Check if any remaining bytes left to decode
+   mov ebx, MMXLength           // ebx ==> x = offset bytes remaining after MMX
+     mov edi, row               // edi ==> Avg(x)
+   cmp ebx, FullLength          // Test if offset at end of array
+   jnb davgend
+         // Do Paeth decode for remaining bytes
+     mov esi, prev_row          // esi ==> Prior(x)
+         mov edx, edi
+         xor ecx, ecx           // zero ecx before using cl & cx in loop below
+         sub edx, bpp           // edx ==> Raw(x-bpp)
+davglp2:
+         // Raw(x) = Avg(x) + ((Raw(x-bpp) + Prior(x))/2)
+         xor eax, eax
+   mov cl, [esi + ebx]        // load cl with Prior(x)
+         mov al, [edx + ebx]    // load al with Raw(x-bpp)
+         add ax, cx
+   inc ebx
+         shr ax, 1              // divide by 2
+         add al, [edi+ebx-1]    // Add Avg(x); -1 to offset inc ebx
+   cmp ebx, FullLength        // Check if at end of array
+   mov [edi+ebx-1], al        // Write back Raw(x);
+                          // mov does not affect flags; -1 to offset inc ebx
+   jb davglp2
+davgend:
+   emms                   // End MMX instructions; prep for possible FP instrs.
+   } // end _asm block
+}
+
+// Optimized code for PNG Paeth filter decoder
+void
+png_read_filter_row_mmx_paeth(png_row_infop row_info, png_bytep row
+                            , png_bytep prev_row)
+{
+      png_uint_32 FullLength;
+      png_uint_32 MMXLength;
+      //png_uint_32 len;
+      int bpp;
+      int diff;
+      //int ptemp;
+      int patemp, pbtemp, pctemp;
+      bpp = (row_info->pixel_depth + 7) >> 3; // Get # bytes per pixel
+      FullLength  = row_info->rowbytes; // # of bytes to filter
+      _asm {
+         xor ebx, ebx                  // ebx ==> x offset
+   mov edi, row
+         xor edx, edx                  // edx ==> x-bpp offset
+   mov esi, prev_row
+         xor eax, eax
+
+     // Compute the Raw value for the first bpp bytes
+     // Note: the formula works out to always be Paeth(x) = Raw(x) + Prior(x)
+     //        where x < bpp
+dpthrlp:
+         mov al, [edi + ebx]
+         add al, [esi + ebx]
+         inc ebx
+         cmp ebx, bpp
+         mov [edi + ebx - 1], al
+         jb dpthrlp
+         // get # of bytes to alignment
+         mov diff, edi         // take start of row
+         add diff, ebx         // add bpp
+   xor ecx, ecx
+         add diff, 0xf         // add 7 + 8 to incr past alignment boundary
+         and diff, 0xfffffff8  // mask to alignment boundary
+         sub diff, edi         // subtract from start ==> value ebx at alignment
+         jz dpthgo
+         // fix alignment
+dpthlp1:
+         xor eax, eax
+         // pav = p - a = (a + b - c) - a = b - c
+         mov al, [esi + ebx]   // load Prior(x) into al
+         mov cl, [esi + edx]   // load Prior(x-bpp) into cl
+         sub eax, ecx          // subtract Prior(x-bpp)
+         mov patemp, eax       // Save pav for later use
+         xor eax, eax
+         // pbv = p - b = (a + b - c) - b = a - c
+         mov al, [edi + edx]   // load Raw(x-bpp) into al
+         sub eax, ecx          // subtract Prior(x-bpp)
+         mov ecx, eax
+         // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+         add eax, patemp       // pcv = pav + pbv
+         // pc = abs(pcv)
+         test eax, 0x80000000
+         jz dpthpca
+         neg eax               // reverse sign of neg values
+dpthpca:
+         mov pctemp, eax       // save pc for later use
+         // pb = abs(pbv)
+         test ecx, 0x80000000
+         jz dpthpba
+         neg ecx               // reverse sign of neg values
+dpthpba:
+         mov pbtemp, ecx       // save pb for later use
+         // pa = abs(pav)
+         mov eax, patemp
+         test eax, 0x80000000
+         jz dpthpaa
+         neg eax               // reverse sign of neg values
+dpthpaa:
+         mov patemp, eax       // save pa for later use
+         // test if pa <= pb
+         cmp eax, ecx
+         jna dpthabb
+         // pa > pb; now test if pb <= pc
+         cmp ecx, pctemp
+         jna dpthbbc
+         // pb > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         jmp dpthpaeth
+dpthbbc:
+         // pb <= pc; Raw(x) = Paeth(x) + Prior(x)
+         mov cl, [esi + ebx]   // load Prior(x) into cl
+         jmp dpthpaeth
+dpthabb:
+         // pa <= pb; now test if pa <= pc
+         cmp eax, pctemp
+         jna dpthabc
+         // pa > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         jmp dpthpaeth
+dpthabc:
+         // pa <= pc; Raw(x) = Paeth(x) + Raw(x-bpp)
+         mov cl, [edi + edx]  // load Raw(x-bpp) into cl
+dpthpaeth:
+   inc ebx
+   inc edx
+         // Raw(x) = (Paeth(x) + Paeth_Predictor( a, b, c )) mod 256
+         add [edi + ebx - 1], cl
+   cmp ebx, diff
+   jb dpthlp1
+dpthgo:
+    mov ecx, FullLength
+         mov eax, ecx
+         sub eax, ebx          // subtract alignment fix
+         and eax, 0x00000007   // calc bytes over mult of 8
+         sub ecx, eax          // drop over bytes from original length
+         mov MMXLength, ecx
+     } // end _asm block
+      // Now do the math for the rest of the row
+      switch ( bpp )
+      {
+      case 3:
+      {
+         ActiveMask.use = 0x0000000000ffffff;
+         ActiveMaskEnd.use = 0xffff000000000000;
+         ShiftBpp.use = 24;    // == bpp(3) * 8
+         ShiftRem.use = 40;    // == 64 - 24
+      _asm {
+            mov ebx, diff
+         mov edi, row
+         mov esi, prev_row
+            pxor mm0, mm0
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]
+dpth3lp:
+            psrlq mm1, ShiftRem     // shift last 3 bytes to 1st 3 bytes
+            movq mm2, [esi + ebx]   // load b=Prior(x)
+            punpcklbw mm1, mm0      // Unpack High bytes of a
+            movq mm3, [esi+ebx-8]   // Prep c=Prior(x-bpp) bytes
+            punpcklbw mm2, mm0      // Unpack High bytes of b
+            psrlq mm3, ShiftRem     // shift last 3 bytes to 1st 3 bytes
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            punpcklbw mm3, mm0      // Unpack High bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4        // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4           // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5        // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5           // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6        // Create mask pcv bytes < 0
+            pand mm0, mm6           // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5        // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6           // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+            movq mm3, [esi + ebx]   // load c=Prior(x-bpp)
+            pand mm7, ActiveMask
+            movq mm2, mm3           // load b=Prior(x) step 1
+            paddb mm7, [edi + ebx]  // add Paeth predictor with Raw(x)
+            punpcklbw mm3, mm0      // Unpack High bytes of c
+            movq [edi + ebx], mm7   // write back updated value
+            movq mm1, mm7           // Now mm1 will be used as Raw(x-bpp)
+            // Now do Paeth for 2nd set of bytes (3-5)
+            psrlq mm2, ShiftBpp     // load b=Prior(x) step 2
+            punpcklbw mm1, mm0      // Unpack High bytes of a
+            pxor mm7, mm7
+            punpcklbw mm2, mm0      // Unpack High bytes of b
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            psubw mm5, mm3
+            psubw mm4, mm3
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) =
+            //       pav + pbv = pbv + pav
+            movq mm6, mm5
+            paddw mm6, mm4
+
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm5           // Create mask pbv bytes < 0
+            pcmpgtw mm7, mm4           // Create mask pav bytes < 0
+            pand mm0, mm5              // Only pbv bytes < 0 in mm0
+            pand mm7, mm4              // Only pav bytes < 0 in mm7
+            psubw mm5, mm0
+            psubw mm4, mm7
+            psubw mm5, mm0
+            psubw mm4, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6           // Create mask pcv bytes < 0
+            pand mm0, mm6              // Only pav bytes < 0 in mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5           // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6           // pab > pc?
+            movq mm2, [esi + ebx]      // load b=Prior(x)
+            pand mm3, mm7
+            pandn mm7, mm0
+            pxor mm1, mm1
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+            movq mm3, mm2           // load c=Prior(x-bpp) step 1
+            pand mm7, ActiveMask
+            punpckhbw mm2, mm0      // Unpack High bytes of b
+            psllq mm7, ShiftBpp     // Shift bytes to 2nd group of 3 bytes
+             // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            paddb mm7, [edi + ebx]  // add Paeth predictor with Raw(x)
+            psllq mm3, ShiftBpp     // load c=Prior(x-bpp) step 2
+            movq [edi + ebx], mm7   // write back updated value
+            movq mm1, mm7
+            punpckhbw mm3, mm0      // Unpack High bytes of c
+            psllq mm1, ShiftBpp     // Shift bytes
+                                    // Now mm1 will be used as Raw(x-bpp)
+            // Now do Paeth for 3rd, and final, set of bytes (6-7)
+            pxor mm7, mm7
+            punpckhbw mm1, mm0      // Unpack High bytes of a
+            psubw mm4, mm3
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            pxor mm0, mm0
+            paddw mm6, mm5
+
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4        // Create mask pav bytes < 0
+            pcmpgtw mm7, mm5        // Create mask pbv bytes < 0
+            pand mm0, mm4           // Only pav bytes < 0 in mm7
+            pand mm7, mm5           // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6        // Create mask pcv bytes < 0
+            pand mm0, mm6           // Only pav bytes < 0 in mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5        // pa > pb?
+            movq mm0, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            pandn mm0, mm1
+            pandn mm7, mm4
+            paddw mm0, mm2
+            paddw mm7, mm5
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6        // pab > pc?
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm1, mm1
+            packuswb mm1, mm7
+            // Step ebx to next set of 8 bytes and repeat loop til done
+      add ebx, 8
+            pand mm1, ActiveMaskEnd
+            paddb mm1, [edi + ebx - 8] // add Paeth predictor with Raw(x)
+
+      cmp ebx, MMXLength
+            pxor mm0, mm0              // pxor does not affect flags
+            movq [edi + ebx - 8], mm1  // write back updated value
+                                 // mm1 will be used as Raw(x-bpp) next loop
+                           // mm3 ready to be used as Prior(x-bpp) next loop
+      jb dpth3lp
+  } // end _asm block
+      }
+      break;
+      case 6:
+      case 7:
+      case 5:
+      {
+         ActiveMask.use  = 0x00000000ffffffff;
+         ActiveMask2.use = 0xffffffff00000000;
+         ShiftBpp.use = bpp << 3;    // == bpp * 8
+         ShiftRem.use = 64 - ShiftBpp.use;
+    _asm {
+            mov ebx, diff
+         mov edi, row               //
+         mov esi, prev_row
+            // PRIME the pump (load the first Raw(x-bpp) data set
+      movq mm1, [edi+ebx-8]
+            pxor mm0, mm0
+dpth6lp:
+            // Must shift to position Raw(x-bpp) data
+            psrlq mm1, ShiftRem
+            // Do first set of 4 bytes
+      movq mm3, [esi+ebx-8]      // read c=Prior(x-bpp) bytes
+            punpcklbw mm1, mm0      // Unpack Low bytes of a
+            movq mm2, [esi + ebx]   // load b=Prior(x)
+            punpcklbw mm2, mm0      // Unpack Low bytes of b
+            // Must shift to position Prior(x-bpp) data
+            psrlq mm3, ShiftRem
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            punpcklbw mm3, mm0      // Unpack Low bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4        // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4           // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5        // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5           // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6        // Create mask pcv bytes < 0
+            pand mm0, mm6           // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5        // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6        // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+            movq mm3, [esi + ebx - 8]  // load c=Prior(x-bpp)
+            pand mm7, ActiveMask
+            psrlq mm3, ShiftRem
+            movq mm2, [esi + ebx]      // load b=Prior(x) step 1
+            paddb mm7, [edi + ebx]     // add Paeth predictor with Raw(x)
+            movq mm6, mm2
+            movq [edi + ebx], mm7      // write back updated value
+        movq mm1, [edi+ebx-8]
+            psllq mm6, ShiftBpp
+            movq mm5, mm7
+            psrlq mm1, ShiftRem
+            por mm3, mm6
+            psllq mm5, ShiftBpp
+            punpckhbw mm3, mm0         // Unpack High bytes of c
+            por mm1, mm5
+            // Do second set of 4 bytes
+            punpckhbw mm2, mm0         // Unpack High bytes of b
+            punpckhbw mm1, mm0         // Unpack High bytes of a
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4           // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4              // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5           // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5              // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6           // Create mask pcv bytes < 0
+            pand mm0, mm6              // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5           // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6           // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            pxor mm1, mm1
+            paddw mm7, mm3
+            pxor mm0, mm0
+            // Step ex to next set of 8 bytes and repeat loop til done
+      add ebx, 8
+            packuswb mm1, mm7
+            paddb mm1, [edi + ebx - 8]     // add Paeth predictor with Raw(x)
+      cmp ebx, MMXLength
+            movq [edi + ebx - 8], mm1      // write back updated value
+                                // mm1 will be used as Raw(x-bpp) next loop
+      jb dpth6lp
+  } // end _asm block
+      }
+      break;
+      case 4:
+      {
+         ActiveMask.use  = 0x00000000ffffffff;
+  _asm {
+            mov ebx, diff
+         mov edi, row               //
+         mov esi, prev_row
+            pxor mm0, mm0
+            // PRIME the pump (load the first Raw(x-bpp) data set
+      movq mm1, [edi+ebx-8] // Only time should need to read a=Raw(x-bpp) bytes
+dpth4lp:
+            // Do first set of 4 bytes
+          movq mm3, [esi+ebx-8]      // read c=Prior(x-bpp) bytes
+            punpckhbw mm1, mm0       // Unpack Low bytes of a
+            movq mm2, [esi + ebx]    // load b=Prior(x)
+            punpcklbw mm2, mm0       // Unpack High bytes of b
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            punpckhbw mm3, mm0       // Unpack High bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4           // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4              // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5           // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5              // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6           // Create mask pcv bytes < 0
+            pand mm0, mm6              // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5           // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6           // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+            movq mm3, [esi + ebx]      // load c=Prior(x-bpp)
+            pand mm7, ActiveMask
+            movq mm2, mm3              // load b=Prior(x) step 1
+            paddb mm7, [edi + ebx]     // add Paeth predictor with Raw(x)
+            punpcklbw mm3, mm0         // Unpack High bytes of c
+            movq [edi + ebx], mm7      // write back updated value
+            movq mm1, mm7              // Now mm1 will be used as Raw(x-bpp)
+            // Do second set of 4 bytes
+            punpckhbw mm2, mm0         // Unpack Low bytes of b
+            punpcklbw mm1, mm0         // Unpack Low bytes of a
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4           // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4              // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5           // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5              // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6           // Create mask pcv bytes < 0
+            pand mm0, mm6              // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5           // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6           // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            pxor mm1, mm1
+            paddw mm7, mm3
+            pxor mm0, mm0
+            // Step ex to next set of 8 bytes and repeat loop til done
+        add ebx, 8
+            packuswb mm1, mm7
+            paddb mm1, [edi + ebx - 8]     // add Paeth predictor with Raw(x)
+      cmp ebx, MMXLength
+            movq [edi + ebx - 8], mm1      // write back updated value
+                                // mm1 will be used as Raw(x-bpp) next loop
+      jb dpth4lp
+  } // end _asm block
+      }
+      break;
+      case 8:                          // bpp == 8
+      {
+         ActiveMask.use  = 0x00000000ffffffff;
+   _asm {
+            mov ebx, diff
+         mov edi, row               //
+         mov esi, prev_row
+            pxor mm0, mm0
+            // PRIME the pump (load the first Raw(x-bpp) data set
+      movq mm1, [edi+ebx-8] // Only time should need to read a=Raw(x-bpp) bytes
+dpth8lp:
+            // Do first set of 4 bytes
+      movq mm3, [esi+ebx-8]      // read c=Prior(x-bpp) bytes
+            punpcklbw mm1, mm0         // Unpack Low bytes of a
+            movq mm2, [esi + ebx]      // load b=Prior(x)
+            punpcklbw mm2, mm0         // Unpack Low bytes of b
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            punpcklbw mm3, mm0         // Unpack Low bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4           // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4              // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5           // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5              // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6           // Create mask pcv bytes < 0
+            pand mm0, mm6              // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5           // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6           // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+        movq mm3, [esi+ebx-8]    // read c=Prior(x-bpp) bytes
+            pand mm7, ActiveMask
+            movq mm2, [esi + ebx]      // load b=Prior(x)
+            paddb mm7, [edi + ebx]     // add Paeth predictor with Raw(x)
+            punpckhbw mm3, mm0         // Unpack High bytes of c
+            movq [edi + ebx], mm7      // write back updated value
+        movq mm1, [edi+ebx-8]    // read a=Raw(x-bpp) bytes
+
+            // Do second set of 4 bytes
+            punpckhbw mm2, mm0         // Unpack High bytes of b
+            punpckhbw mm1, mm0         // Unpack High bytes of a
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4           // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4              // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5           // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5              // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6           // Create mask pcv bytes < 0
+            pand mm0, mm6              // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5           // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6           // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            pxor mm1, mm1
+            paddw mm7, mm3
+            pxor mm0, mm0
+            // Step ex to next set of 8 bytes and repeat loop til done
+        add ebx, 8
+            packuswb mm1, mm7
+            paddb mm1, [edi + ebx - 8]     // add Paeth predictor with Raw(x)
+        cmp ebx, MMXLength
+            movq [edi + ebx - 8], mm1      // write back updated value
+                            // mm1 will be used as Raw(x-bpp) next loop
+        jb dpth8lp
+      } // end _asm block
+      }
+      break;
+      case 1:                          // bpp = 1
+      case 2:                          // bpp = 2
+      default:                         // bpp > 8
+      {
+   _asm {
+      mov ebx, diff
+      cmp ebx, FullLength
+      jnb dpthdend
+        mov edi, row               //
+        mov esi, prev_row
+            // Do Paeth decode for remaining bytes
+            mov edx, ebx
+            xor ecx, ecx        // zero ecx before using cl & cx in loop below
+            sub edx, bpp        // Set edx = ebx - bpp
+dpthdlp:
+            xor eax, eax
+            // pav = p - a = (a + b - c) - a = b - c
+            mov al, [esi + ebx]        // load Prior(x) into al
+            mov cl, [esi + edx]        // load Prior(x-bpp) into cl
+            sub eax, ecx                 // subtract Prior(x-bpp)
+            mov patemp, eax                 // Save pav for later use
+            xor eax, eax
+            // pbv = p - b = (a + b - c) - b = a - c
+            mov al, [edi + edx]        // load Raw(x-bpp) into al
+            sub eax, ecx                 // subtract Prior(x-bpp)
+            mov ecx, eax
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            add eax, patemp                 // pcv = pav + pbv
+            // pc = abs(pcv)
+            test eax, 0x80000000
+            jz dpthdpca
+            neg eax                     // reverse sign of neg values
+dpthdpca:
+            mov pctemp, eax             // save pc for later use
+            // pb = abs(pbv)
+            test ecx, 0x80000000
+            jz dpthdpba
+            neg ecx                     // reverse sign of neg values
+dpthdpba:
+            mov pbtemp, ecx             // save pb for later use
+            // pa = abs(pav)
+            mov eax, patemp
+            test eax, 0x80000000
+            jz dpthdpaa
+            neg eax                     // reverse sign of neg values
+dpthdpaa:
+            mov patemp, eax             // save pa for later use
+            // test if pa <= pb
+            cmp eax, ecx
+            jna dpthdabb
+            // pa > pb; now test if pb <= pc
+            cmp ecx, pctemp
+            jna dpthdbbc
+            // pb > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+            mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+            jmp dpthdpaeth
+dpthdbbc:
+            // pb <= pc; Raw(x) = Paeth(x) + Prior(x)
+            mov cl, [esi + ebx]        // load Prior(x) into cl
+            jmp dpthdpaeth
+dpthdabb:
+            // pa <= pb; now test if pa <= pc
+            cmp eax, pctemp
+            jna dpthdabc
+            // pa > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+            mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+            jmp dpthdpaeth
+dpthdabc:
+            // pa <= pc; Raw(x) = Paeth(x) + Raw(x-bpp)
+            mov cl, [edi + edx]  // load Raw(x-bpp) into cl
+dpthdpaeth:
+      inc ebx
+      inc edx
+            // Raw(x) = (Paeth(x) + Paeth_Predictor( a, b, c )) mod 256
+            add [edi + ebx - 1], cl
+      cmp ebx, FullLength
+      jb dpthdlp
+dpthdend:
+        } // end _asm block
+      }
+      return;                   // No need to go further with this one
+      }                         // end switch ( bpp )
+      _asm {
+         // MMX acceleration complete now do clean-up
+         // Check if any remaining bytes left to decode
+   mov ebx, MMXLength
+   cmp ebx, FullLength
+   jnb dpthend
+     mov edi, row
+     mov esi, prev_row
+         // Do Paeth decode for remaining bytes
+         mov edx, ebx
+         xor ecx, ecx         // zero ecx before using cl & cx in loop below
+         sub edx, bpp         // Set edx = ebx - bpp
+dpthlp2:
+         xor eax, eax
+         // pav = p - a = (a + b - c) - a = b - c
+         mov al, [esi + ebx]  // load Prior(x) into al
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         sub eax, ecx         // subtract Prior(x-bpp)
+         mov patemp, eax      // Save pav for later use
+         xor eax, eax
+         // pbv = p - b = (a + b - c) - b = a - c
+         mov al, [edi + edx]  // load Raw(x-bpp) into al
+         sub eax, ecx         // subtract Prior(x-bpp)
+         mov ecx, eax
+         // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+         add eax, patemp      // pcv = pav + pbv
+         // pc = abs(pcv)
+         test eax, 0x80000000
+         jz dpthpca2
+         neg eax              // reverse sign of neg values
+dpthpca2:
+         mov pctemp, eax      // save pc for later use
+         // pb = abs(pbv)
+         test ecx, 0x80000000
+         jz dpthpba2
+         neg ecx              // reverse sign of neg values
+dpthpba2:
+         mov pbtemp, ecx      // save pb for later use
+         // pa = abs(pav)
+         mov eax, patemp
+         test eax, 0x80000000
+         jz dpthpaa2
+         neg eax              // reverse sign of neg values
+dpthpaa2:
+         mov patemp, eax      // save pa for later use
+         // test if pa <= pb
+         cmp eax, ecx
+         jna dpthabb2
+         // pa > pb; now test if pb <= pc
+         cmp ecx, pctemp
+         jna dpthbbc2
+         // pb > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         jmp dpthpaeth2
+dpthbbc2:
+         // pb <= pc; Raw(x) = Paeth(x) + Prior(x)
+         mov cl, [esi + ebx]        // load Prior(x) into cl
+         jmp dpthpaeth2
+dpthabb2:
+         // pa <= pb; now test if pa <= pc
+         cmp eax, pctemp
+         jna dpthabc2
+         // pa > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         jmp dpthpaeth2
+dpthabc2:
+         // pa <= pc; Raw(x) = Paeth(x) + Raw(x-bpp)
+         mov cl, [edi + edx]  // load Raw(x-bpp) into cl
+dpthpaeth2:
+      inc ebx
+      inc edx
+         // Raw(x) = (Paeth(x) + Paeth_Predictor( a, b, c )) mod 256
+         add [edi + ebx - 1], cl
+      cmp ebx, FullLength
+      jb dpthlp2
+dpthend:
+      emms             // End MMX instructions; prep for possible FP instrs.
+     } // end _asm block
+}
+
+// Optimized code for PNG Sub filter decoder
+void
+png_read_filter_row_mmx_sub(png_row_infop row_info, png_bytep row)
+{
+    //int test;
+      int bpp;
+    png_uint_32 FullLength;
+    png_uint_32 MMXLength;
+    int diff;
+      bpp = (row_info->pixel_depth + 7) >> 3; // Get # bytes per pixel
+    FullLength  = row_info->rowbytes - bpp; // # of bytes to filter
+    _asm {
+        mov edi, row
+        mov esi, edi               // lp = row
+            add edi, bpp               // rp = row + bpp
+            xor eax, eax
+            // get # of bytes to alignment
+            mov diff, edi               // take start of row
+            add diff, 0xf               // add 7 + 8 to incr past
+                                        // alignment boundary
+            xor ebx, ebx
+            and diff, 0xfffffff8        // mask to alignment boundary
+            sub diff, edi               // subtract from start ==> value
+                                        //  ebx at alignment
+            jz dsubgo
+            // fix alignment
+dsublp1:
+         mov al, [esi+ebx]
+         add [edi+ebx], al
+          inc ebx
+          cmp ebx, diff
+         jb dsublp1
+dsubgo:
+         mov ecx, FullLength
+            mov edx, ecx
+            sub edx, ebx                  // subtract alignment fix
+            and edx, 0x00000007           // calc bytes over mult of 8
+            sub ecx, edx                  // drop over bytes from length
+            mov MMXLength, ecx
+     } // end _asm block
+      // Now do the math for the rest of the row
+      switch ( bpp )
+      {
+      case 3:
+    {
+         ActiveMask.use  = 0x0000ffffff000000;
+         ShiftBpp.use = 24;       // == 3 * 8
+         ShiftRem.use  = 40;      // == 64 - 24
+      _asm {
+            mov edi, row
+            movq mm7, ActiveMask  // Load ActiveMask for 2nd active byte group
+        mov esi, edi              // lp = row
+            add edi, bpp          // rp = row + bpp
+            movq mm6, mm7
+            mov ebx, diff
+            psllq mm6, ShiftBpp   // Move mask in mm6 to cover 3rd active
+                                  // byte group
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]
+dsub3lp:
+            psrlq mm1, ShiftRem   // Shift data for adding 1st bpp bytes
+                          // no need for mask; shift clears inactive bytes
+            // Add 1st active group
+            movq mm0, [edi+ebx]
+        paddb mm0, mm1
+            // Add 2nd active group
+            movq mm1, mm0         // mov updated Raws to mm1
+            psllq mm1, ShiftBpp   // shift data to position correctly
+            pand mm1, mm7         // mask to use only 2nd active group
+        paddb mm0, mm1
+            // Add 3rd active group
+            movq mm1, mm0         // mov updated Raws to mm1
+            psllq mm1, ShiftBpp   // shift data to position correctly
+            pand mm1, mm6         // mask to use only 3rd active group
+        add ebx, 8
+        paddb mm0, mm1
+        cmp ebx, MMXLength
+        movq [edi+ebx-8], mm0     // Write updated Raws back to array
+            // Prep for doing 1st add at top of loop
+            movq mm1, mm0
+        jb dsub3lp
+      } // end _asm block
+      }
+      break;
+      case 1:
+    {
+      /* Placed here just in case this is a duplicate of the
+      non-MMX code for the SUB filter in png_read_filter_row
+                        above
+      */
+//         png_bytep rp;
+//         png_bytep lp;
+//         png_uint_32 i;
+//         bpp = (row_info->pixel_depth + 7) >> 3;
+//         for (i = (png_uint_32)bpp, rp = row + bpp, lp = row;
+//            i < row_info->rowbytes; i++, rp++, lp++)
+//      {
+//            *rp = (png_byte)(((int)(*rp) + (int)(*lp)) & 0xff);
+//      }
+      _asm {
+            mov ebx, diff
+            mov edi, row
+        cmp ebx, FullLength
+        jnb dsub1end
+        mov esi, edi          // lp = row
+        xor eax, eax
+            add edi, bpp      // rp = row + bpp
+dsub1lp:
+        mov al, [esi+ebx]
+        add [edi+ebx], al
+          inc ebx
+          cmp ebx, FullLength
+        jb dsub1lp
+dsub1end:
+      } // end _asm block
+    }
+      return;
+      case 6:
+      case 7:
+      case 4:
+      case 5:
+    {
+         ShiftBpp.use = bpp << 3;
+         ShiftRem.use = 64 - ShiftBpp.use;
+      _asm {
+            mov edi, row
+            mov ebx, diff
+        mov esi, edi               // lp = row
+            add edi, bpp           // rp = row + bpp
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]
+dsub4lp:
+            psrlq mm1, ShiftRem // Shift data for adding 1st bpp bytes
+                          // no need for mask; shift clears inactive bytes
+        movq mm0, [edi+ebx]
+        paddb mm0, mm1
+            // Add 2nd active group
+            movq mm1, mm0          // mov updated Raws to mm1
+            psllq mm1, ShiftBpp    // shift data to position correctly
+                                   // there is no need for any mask
+                                   // since shift clears inactive bits/bytes
+        add ebx, 8
+        paddb mm0, mm1
+        cmp ebx, MMXLength
+        movq [edi+ebx-8], mm0
+            movq mm1, mm0          // Prep for doing 1st add at top of loop
+        jb dsub4lp
+      } // end _asm block
+      }
+      break;
+      case 2:
+    {
+         ActiveMask.use  = 0x00000000ffff0000;
+         ShiftBpp.use = 16;       // == 2 * 8
+         ShiftRem.use = 48;       // == 64 - 16
+      _asm {
+            movq mm7, ActiveMask  // Load ActiveMask for 2nd active byte group
+            mov ebx, diff
+            movq mm6, mm7
+        mov edi, row
+            psllq mm6, ShiftBpp // Move mask in mm6 to cover 3rd active byte group
+        mov esi, edi            // lp = row
+            movq mm5, mm6
+            add edi, bpp        // rp = row + bpp
+            psllq mm5, ShiftBpp // Move mask in mm5 to cover 4th active byte group
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]
+dsub2lp:
+            // Add 1st active group
+            psrlq mm1, ShiftRem    // Shift data for adding 1st bpp bytes
+                                 // no need for mask; shift clears inactive bytes
+            movq mm0, [edi+ebx]
+        paddb mm0, mm1
+            // Add 2nd active group
+            movq mm1, mm0              // mov updated Raws to mm1
+            psllq mm1, ShiftBpp      // shift data to position correctly
+            pand mm1, mm7              // mask to use only 2nd active group
+        paddb mm0, mm1
+            // Add 3rd active group
+            movq mm1, mm0              // mov updated Raws to mm1
+            psllq mm1, ShiftBpp      // shift data to position correctly
+            pand mm1, mm6              // mask to use only 3rd active group
+        paddb mm0, mm1
+            // Add 4th active group
+            movq mm1, mm0              // mov updated Raws to mm1
+            psllq mm1, ShiftBpp      // shift data to position correctly
+            pand mm1, mm5              // mask to use only 4th active group
+        add ebx, 8
+        paddb mm0, mm1
+        cmp ebx, MMXLength
+        movq [edi+ebx-8], mm0        // Write updated Raws back to array
+            movq mm1, mm0            // Prep for doing 1st add at top of loop
+        jb dsub2lp
+      } // end _asm block
+      }
+      break;
+      case 8:
+    {
+      _asm {
+        mov edi, row
+            mov ebx, diff
+        mov esi, edi               // lp = row
+            add edi, bpp             // rp = row + bpp
+         mov ecx, MMXLength
+            movq mm7, [edi+ebx-8]   // PRIME the pump (load the first
+                                    // Raw(x-bpp) data set
+            and ecx, 0x0000003f     // calc bytes over mult of 64
+dsub8lp:
+        movq mm0, [edi+ebx]         // Load Sub(x) for 1st 8 bytes
+        paddb mm0, mm7
+               movq mm1, [edi+ebx+8]   // Load Sub(x) for 2nd 8 bytes
+        movq [edi+ebx], mm0        // Write Raw(x) for 1st 8 bytes
+                                   // Now mm0 will be used as Raw(x-bpp) for
+                                   // the 2nd group of 8 bytes.  This will be
+                                   // repeated for each group of 8 bytes with
+                                   // the 8th group being used as the Raw(x-bpp)
+                                   // for the 1st group of the next loop.
+        paddb mm1, mm0
+        movq mm2, [edi+ebx+16]      // Load Sub(x) for 3rd 8 bytes
+        movq [edi+ebx+8], mm1      // Write Raw(x) for 2nd 8 bytes
+        paddb mm2, mm1
+        movq mm3, [edi+ebx+24]      // Load Sub(x) for 4th 8 bytes
+        movq [edi+ebx+16], mm2      // Write Raw(x) for 3rd 8 bytes
+        paddb mm3, mm2
+        movq mm4, [edi+ebx+32] // Load Sub(x) for 5th 8 bytes
+        movq [edi+ebx+24], mm3      // Write Raw(x) for 4th 8 bytes
+        paddb mm4, mm3
+        movq mm5, [edi+ebx+40] // Load Sub(x) for 6th 8 bytes
+        movq [edi+ebx+32], mm4      // Write Raw(x) for 5th 8 bytes
+        paddb mm5, mm4
+        movq mm6, [edi+ebx+48]  // Load Sub(x) for 7th 8 bytes
+        movq [edi+ebx+40], mm5      // Write Raw(x) for 6th 8 bytes
+        paddb mm6, mm5
+        movq mm7, [edi+ebx+56]      // Load Sub(x) for 8th 8 bytes
+        movq [edi+ebx+48], mm6      // Write Raw(x) for 7th 8 bytes
+        add ebx, 64
+        paddb mm7, mm6
+        cmp ebx, ecx
+        movq [edi+ebx-8], mm7      // Write Raw(x) for 8th 8 bytes
+        jb dsub8lp
+        cmp ebx, MMXLength
+        jnb dsub8lt8
+dsub8lpA:
+            movq mm0, [edi+ebx]
+        add ebx, 8
+        paddb mm0, mm7
+        cmp ebx, MMXLength
+        movq [edi+ebx-8], mm0   // use -8 to offset early add to ebx
+            movq mm7, mm0       // Move calculated Raw(x) data to mm1 to
+                                // be the new Raw(x-bpp) for the next loop
+        jb dsub8lpA
+dsub8lt8:
+      } // end _asm block
+      }
+      break;
+      default:                // bpp greater than 8 bytes
+    {
+      _asm {
+            mov ebx, diff
+        mov edi, row
+        mov esi, edi               // lp = row
+            add edi, bpp           // rp = row + bpp
+dsubAlp:
+        movq mm0, [edi+ebx]
+        movq mm1, [esi+ebx]
+        add ebx, 8
+        paddb mm0, mm1
+        cmp ebx, MMXLength
+        movq [edi+ebx-8], mm0 // mov does not affect flags; -8 to offset add ebx
+        jb dsubAlp
+      } // end _asm block
+      }
+      break;
+      }                                // end switch ( bpp )
+
+      _asm {
+            mov ebx, MMXLength
+            mov edi, row
+        cmp ebx, FullLength
+        jnb dsubend
+        mov esi, edi               // lp = row
+        xor eax, eax
+            add edi, bpp           // rp = row + bpp
+dsublp2:
+        mov al, [esi+ebx]
+        add [edi+ebx], al
+          inc ebx
+          cmp ebx, FullLength
+        jb dsublp2
+dsubend:
+         emms             // End MMX instructions; prep for possible FP instrs.
+    } // end _asm block
+}
+
+// Optimized code for PNG Up filter decoder
+void
+png_read_filter_row_mmx_up(png_row_infop row_info, png_bytep row,
+   png_bytep prev_row)
+{
+      png_uint_32 len;
+    len  = row_info->rowbytes;       // # of bytes to filter
+    _asm {
+      mov edi, row
+         // get # of bytes to alignment
+         mov ecx, edi
+       xor ebx, ebx
+         add ecx, 0x7
+         xor eax, eax
+         and ecx, 0xfffffff8
+      mov esi, prev_row
+         sub ecx, edi
+         jz dupgo
+         // fix alignment
+duplp1:
+      mov al, [edi+ebx]
+      add al, [esi+ebx]
+      inc ebx
+      cmp ebx, ecx
+      mov [edi + ebx-1], al  // mov does not affect flags; -1 to offset inc ebx
+      jb duplp1
+dupgo:
+      mov ecx, len
+         mov edx, ecx
+         sub edx, ebx                  // subtract alignment fix
+         and edx, 0x0000003f           // calc bytes over mult of 64
+         sub ecx, edx                  // drop over bytes from length
+         // Unrolled loop - use all MMX registers and interleave to reduce
+         // number of branch instructions (loops) and reduce partial stalls
+duploop:
+      movq mm1, [esi+ebx]
+      movq mm0, [edi+ebx]
+          movq mm3, [esi+ebx+8]
+      paddb mm0, mm1
+          movq mm2, [edi+ebx+8]
+      movq [edi+ebx], mm0
+          paddb mm2, mm3
+            movq mm5, [esi+ebx+16]
+          movq [edi+ebx+8], mm2
+            movq mm4, [edi+ebx+16]
+               movq mm7, [esi+ebx+24]
+            paddb mm4, mm5
+               movq mm6, [edi+ebx+24]
+            movq [edi+ebx+16], mm4
+               paddb mm6, mm7
+      movq mm1, [esi+ebx+32]
+               movq [edi+ebx+24], mm6
+      movq mm0, [edi+ebx+32]
+         movq mm3, [esi+ebx+40]
+      paddb mm0, mm1
+         movq mm2, [edi+ebx+40]
+      movq [edi+ebx+32], mm0
+         paddb mm2, mm3
+            movq mm5, [esi+ebx+48]
+         movq [edi+ebx+40], mm2
+            movq mm4, [edi+ebx+48]
+               movq mm7, [esi+ebx+56]
+            paddb mm4, mm5
+               movq mm6, [edi+ebx+56]
+            movq [edi+ebx+48], mm4
+         add ebx, 64
+               paddb mm6, mm7
+      cmp ebx, ecx
+               movq [edi+ebx-8], mm6 // (+56)movq does not affect flags;
+                                     // -8 to offset add ebx
+      jb duploop
+
+      cmp edx, 0                     // Test for bytes over mult of 64
+      jz dupend
+
+
+         // 2 lines added by lcreeve@netins.net
+         // (mail 11 Jul 98 in png-implement list)
+         cmp edx, 8 //test for less than 8 bytes
+         jb duplt8
+
+
+         add ecx, edx
+         and edx, 0x00000007           // calc bytes over mult of 8
+         sub ecx, edx                  // drop over bytes from length
+      jz duplt8
+         // Loop using MMX registers mm0 & mm1 to update 8 bytes simultaneously
+duplpA:
+      movq mm1, [esi+ebx]
+      movq mm0, [edi+ebx]
+      add ebx, 8
+      paddb mm0, mm1
+      cmp ebx, ecx
+      movq [edi+ebx-8], mm0 // movq does not affect flags; -8 to offset add ebx
+      jb duplpA
+      cmp edx, 0            // Test for bytes over mult of 8
+      jz dupend
+duplt8:
+         xor eax, eax
+      add ecx, edx          // move over byte count into counter
+         // Loop using x86 registers to update remaining bytes
+duplp2:
+      mov al, [edi + ebx]
+      add al, [esi + ebx]
+      inc ebx
+      cmp ebx, ecx
+      mov [edi + ebx-1], al // mov does not affect flags; -1 to offset inc ebx
+      jb duplp2
+dupend:
+         // Conversion of filtered row completed
+      emms          // End MMX instructions; prep for possible FP instrs.
+    } // end _asm block
+}
+
+
+
+// Optimized png_read_filter_row routines
+void
+png_read_filter_row(png_structp png_ptr, png_row_infop row_info, png_bytep
+   row, png_bytep prev_row, int filter)
+{
+   char filnm[6];
+   #define UseMMX (1)
+
+
+   if (mmx_supported==2)
+       mmx_supported=mmxsupport();
+   //if (!mmx_supported)
+   {
+       png_read_filter_row_c(png_ptr, row_info, row, prev_row, filter);
+       return ;
+   }
+
+
+   png_debug(1, "in png_read_filter_row\n");
+   png_debug1(0,"%s, ", (UseMMX?"MMX":"x86"));
+   switch (filter)
+   {
+   case 0: sprintf(filnm, "None ");
+      break;
+   case 1: sprintf(filnm, "Sub  ");
+      break;
+   case 2: sprintf(filnm, "Up   ");
+      break;
+   case 3: sprintf(filnm, "Avg  ");
+      break;
+   case 4: sprintf(filnm, "Paeth");
+      break;
+   default: sprintf(filnm, "Unknw");
+      break;
+   }
+   png_debug2(0,"row=%5d, %s, ", png_ptr->row_number, filnm);
+   png_debug2(0, "pd=%2d, b=%d, ", (int)row_info->pixel_depth,
+      (int)((row_info->pixel_depth + 7) >> 3));
+   png_debug1(0,"len=%8d, ", row_info->rowbytes);
+
+   switch (filter)
+   {
+      case PNG_FILTER_VALUE_NONE:
+         break;
+      case PNG_FILTER_VALUE_SUB:
+      {
+         if ( UseMMX && (row_info->pixel_depth > 8) &&
+            (row_info->rowbytes >= 128) )
+         {
+            png_read_filter_row_mmx_sub(row_info, row);
+         }  //end if UseMMX
+         else
+         {
+            int bpp;
+            png_bytep rp;
+            png_bytep lp;
+            png_uint_32 i;
+            bpp = (row_info->pixel_depth + 7) >> 3;
+            for (i = (png_uint_32)bpp, rp = row + bpp, lp = row;
+               i < row_info->rowbytes; i++, rp++, lp++)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*lp)) & 0xff);
+         }
+         }  //end !UseMMX
+         break;
+      }
+      case PNG_FILTER_VALUE_UP:
+      {
+         if ( UseMMX && (row_info->pixel_depth > 8) &&
+             (row_info->rowbytes >= 128) )
+         {
+            png_read_filter_row_mmx_up(row_info, row, prev_row);
+         }  //end if UseMMX
+         else
+         {
+            png_bytep rp;
+            png_bytep pp;
+            png_uint_32 i;
+            for (i = 0, rp = row, pp = prev_row;
+               i < row_info->rowbytes; i++, rp++, pp++)
+            {
+                  *rp = (png_byte)(((int)(*rp) + (int)(*pp)) & 0xff);
+            }
+         }  //end !UseMMX
+         break;
+      }
+      case PNG_FILTER_VALUE_AVG:
+      {
+         if ( UseMMX && (row_info->pixel_depth > 8) &&
+             (row_info->rowbytes >= 128) )
+         {
+            png_read_filter_row_mmx_avg(row_info, row, prev_row);
+         }  //end if UseMMX
+         else
+         {
+      png_uint_32 i;
+      int bpp;
+      png_bytep rp;
+      png_bytep pp;
+      png_bytep lp;
+            bpp = (row_info->pixel_depth + 7) >> 3;
+            for (i = 0, rp = row, pp = prev_row;
+               i < (png_uint_32)bpp; i++, rp++, pp++)
+      {
+               *rp = (png_byte)(((int)(*rp) +
+                  ((int)(*pp) / 2)) & 0xff);
+      }
+            for (lp = row; i < row_info->rowbytes; i++, rp++, lp++, pp++)
+      {
+               *rp = (png_byte)(((int)(*rp) +
+                  (int)(*pp + *lp) / 2) & 0xff);
+      }
+         }  //end !UseMMX
+         break;
+      }
+      case PNG_FILTER_VALUE_PAETH:
+      {
+         if ( UseMMX && (row_info->pixel_depth > 8) &&
+             (row_info->rowbytes >= 128) )
+         {
+            png_read_filter_row_mmx_paeth(row_info, row, prev_row);
+         }  //end if UseMMX
+         else
+         {
+            int bpp;
+            png_uint_32 i;
+            png_bytep rp;
+            png_bytep pp;
+            png_bytep lp;
+            png_bytep cp;
+            bpp = (row_info->pixel_depth + 7) >> 3;
+            for (i = 0, rp = row, pp = prev_row;
+               i < (png_uint_32)bpp; i++, rp++, pp++)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*pp)) & 0xff);
+            }
+            for (lp = rp - bpp, cp = pp - bpp;
+               i < row_info->rowbytes; i++, rp++, pp++, lp++, cp++)
+            {
+               int a, b, c, pa, pb, pc, p;
+               b = *pp;
+               c = *cp;
+               a = *lp;
+               p = a + b - c;
+               pa = abs(p - a);
+               pb = abs(p - b);
+               pc = abs(p - c);
+               if (pa <= pb && pa <= pc)
+                  p = a;
+               else if (pb <= pc)
+                  p = b;
+               else
+                  p = c;
+               *rp = (png_byte)(((int)(*rp) + p) & 0xff);
+            }
+         }  //end !UseMMX
+         break;
+      }
+      default:
+         png_error(png_ptr, "Bad adaptive filter type");
+         break;
+   }
+}
+#endif