AltiVec SIMD implementation of RGB-to-Grayscale color conversion


git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1471 632fc199-4ca6-4c93-a231-07263d6284db
diff --git a/simd/Makefile.am b/simd/Makefile.am
index 8701194..7aa36ae 100644
--- a/simd/Makefile.am
+++ b/simd/Makefile.am
@@ -73,12 +73,13 @@
 if SIMD_POWERPC
 
 libsimd_la_SOURCES = jsimd_powerpc.c \
-	jccolor-altivec.c \
+	jccolor-altivec.c     jcgray-altivec.c \
 	jfdctfst-altivec.c    jfdctint-altivec.c \
 	jidctfst-altivec.c    jidctint-altivec.c
 libsimd_la_CFLAGS = -maltivec
 
 jccolor-altivec.lo:  jccolext-altivec.c
+jcgray-altivec.lo:   jcgryext-altivec.c
 
 endif
 
diff --git a/simd/jcgray-altivec.c b/simd/jcgray-altivec.c
new file mode 100644
index 0000000..b52fade
--- /dev/null
+++ b/simd/jcgray-altivec.c
@@ -0,0 +1,99 @@
+/*
+ * AltiVec optimizations for libjpeg-turbo
+ *
+ * Copyright (C) 2014, D. R. Commander.
+ * All rights reserved.
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+/* RGB --> GRAYSCALE CONVERSION */
+
+#include "jsimd_altivec.h"
+
+
+#define F_0_114 7471                 /* FIX(0.11400) */
+#define F_0_250 16384                /* FIX(0.25000) */
+#define F_0_299 19595                /* FIX(0.29900) */
+#define F_0_587 38470                /* FIX(0.58700) */
+#define F_0_337 (F_0_587 - F_0_250)  /* FIX(0.58700) - FIX(0.25000) */
+
+#define SCALEBITS 16
+#define ONE_HALF (1 << (SCALEBITS - 1))
+
+
+#define RGBG_INDEX0 {0,1,3,4,6,7,9,10,2,1,5,4,8,7,11,10}
+#define RGBG_INDEX1 {12,13,15,16,18,19,21,22,14,13,17,16,20,19,23,22}
+#define RGBG_INDEX2 {8,9,11,12,14,15,17,18,10,9,13,12,16,15,19,18}
+#define RGBG_INDEX3 {4,5,7,8,10,11,13,14,6,5,9,8,12,11,15,14}
+#include "jcgryext-altivec.c"
+#undef RGB_PIXELSIZE
+
+#define RGB_PIXELSIZE EXT_RGB_PIXELSIZE
+#define jsimd_rgb_gray_convert_altivec jsimd_extrgb_gray_convert_altivec
+#include "jcgryext-altivec.c"
+#undef RGB_PIXELSIZE
+#undef RGBG_INDEX0
+#undef RGBG_INDEX1
+#undef RGBG_INDEX2
+#undef RGBG_INDEX3
+#undef jsimd_rgb_gray_convert_altivec
+
+#define RGB_PIXELSIZE EXT_RGBX_PIXELSIZE
+#define RGBG_INDEX {0,1,4,5,8,9,12,13,2,1,6,5,10,9,14,13}
+#define jsimd_rgb_gray_convert_altivec jsimd_extrgbx_gray_convert_altivec
+#include "jcgryext-altivec.c"
+#undef RGB_PIXELSIZE
+#undef RGBG_INDEX
+#undef jsimd_rgb_gray_convert_altivec
+
+#define RGB_PIXELSIZE EXT_BGR_PIXELSIZE
+#define RGBG_INDEX0 {2,1,5,4,8,7,11,10,0,1,3,4,6,7,9,10}
+#define RGBG_INDEX1 {14,13,17,16,20,19,23,22,12,13,15,16,18,19,21,22}
+#define RGBG_INDEX2 {10,9,13,12,16,15,19,18,8,9,11,12,14,15,17,18}
+#define RGBG_INDEX3 {6,5,9,8,12,11,15,14,4,5,7,8,10,11,13,14}
+#define jsimd_rgb_gray_convert_altivec jsimd_extbgr_gray_convert_altivec
+#include "jcgryext-altivec.c"
+#undef RGB_PIXELSIZE
+#undef RGBG_INDEX0
+#undef RGBG_INDEX1
+#undef RGBG_INDEX2
+#undef RGBG_INDEX3
+#undef jsimd_rgb_gray_convert_altivec
+
+#define RGB_PIXELSIZE EXT_BGRX_PIXELSIZE
+#define RGBG_INDEX {2,1,6,5,10,9,14,13,0,1,4,5,8,9,12,13}
+#define jsimd_rgb_gray_convert_altivec jsimd_extbgrx_gray_convert_altivec
+#include "jcgryext-altivec.c"
+#undef RGB_PIXELSIZE
+#undef RGBG_INDEX
+#undef jsimd_rgb_gray_convert_altivec
+
+#define RGB_PIXELSIZE EXT_XBGR_PIXELSIZE
+#define RGBG_INDEX {3,2,7,6,11,10,15,14,1,2,5,6,9,10,13,14}
+#define jsimd_rgb_gray_convert_altivec jsimd_extxbgr_gray_convert_altivec
+#include "jcgryext-altivec.c"
+#undef RGB_PIXELSIZE
+#undef RGBG_INDEX
+#undef jsimd_rgb_gray_convert_altivec
+
+#define RGB_PIXELSIZE EXT_XRGB_PIXELSIZE
+#define RGBG_INDEX {1,2,5,6,9,10,13,14,3,2,7,6,11,10,15,14}
+#define jsimd_rgb_gray_convert_altivec jsimd_extxrgb_gray_convert_altivec
+#include "jcgryext-altivec.c"
+#undef RGB_PIXELSIZE
+#undef RGBG_INDEX
+#undef jsimd_rgb_gray_convert_altivec
diff --git a/simd/jcgryext-altivec.c b/simd/jcgryext-altivec.c
new file mode 100644
index 0000000..c1d0a45
--- /dev/null
+++ b/simd/jcgryext-altivec.c
@@ -0,0 +1,200 @@
+/*
+ * AltiVec optimizations for libjpeg-turbo
+ *
+ * Copyright (C) 2014, D. R. Commander.
+ * Copyright (C) 2014, Jay Foad.
+ * All rights reserved.
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+
+/* This file is included by jcgray-altivec.c */
+
+
+void jsimd_rgb_gray_convert_altivec (JDIMENSION img_width,
+                                     JSAMPARRAY input_buf,
+                                     JSAMPIMAGE output_buf,
+                                     JDIMENSION output_row, int num_rows)
+{
+  JSAMPROW inptr, outptr;
+  int pitch;
+  __vector unsigned char rgb0, rgb1 = {0}, rgb2 = {0}, rgb3 = {0}, rgbg0,
+    rgbg1, rgbg2, rgbg3, y;
+#if RGB_PIXELSIZE == 4
+  __vector unsigned char rgb4;
+#endif
+  __vector short rg0, rg1, rg2, rg3, bg0, bg1, bg2, bg3;
+  __vector unsigned short y01, y23;
+  __vector int y0, y1, y2, y3;
+
+  /* Constants */
+  __vector short pw_f0299_f0337 = { __4X2(F_0_299, F_0_337) },
+    pw_f0114_f0250 = { __4X2(F_0_114, F_0_250) };
+  __vector int pd_onehalf = { __4X(ONE_HALF) };
+  __vector unsigned char zero = { __16X(0) },
+    shift_pack_index =
+      { 0, 1, 4, 5, 8, 9, 12, 13, 16, 17, 20, 21, 24, 25, 28, 29};
+
+  while (--num_rows >= 0) {
+    inptr = *input_buf++;
+    outptr = output_buf[0][output_row];
+    output_row++;
+
+    for (pitch = img_width * RGB_PIXELSIZE; pitch > 0;
+         pitch -= RGB_PIXELSIZE * 16, inptr += RGB_PIXELSIZE * 16,
+         outptr += 16) {
+
+#if RGB_PIXELSIZE == 3
+      /* Load 16 pixels == 48 bytes */
+      if ((size_t)inptr & 15) {
+        __vector unsigned char unaligned_shift_index;
+        rgb0 = vec_ld(0, inptr);
+        if (pitch > 16)
+          rgb1 = vec_ld(16, inptr);
+        else
+          rgb1 = vec_ld(-1, inptr + pitch);
+        if (pitch > 32)
+          rgb2 = vec_ld(32, inptr);
+        else
+          rgb2 = vec_ld(-1, inptr + pitch);
+        if (pitch > 48)
+          rgb3 = vec_ld(48, inptr);
+        else
+          rgb3 = vec_ld(-1, inptr + pitch);
+        unaligned_shift_index = vec_lvsl(0, inptr);
+        rgb0 = vec_perm(rgb0, rgb1, unaligned_shift_index);
+        rgb1 = vec_perm(rgb1, rgb2, unaligned_shift_index);
+        rgb2 = vec_perm(rgb2, rgb3, unaligned_shift_index);
+      } else {
+        rgb0 = vec_ld(0, inptr);
+        if (pitch > 16)
+          rgb1 = vec_ld(16, inptr);
+        if (pitch > 32)
+          rgb2 = vec_ld(32, inptr);
+      }
+
+      /* rgb0 = R0 G0 B0 R1 G1 B1 R2 G2 B2 R3 G3 B3 R4 G4 B4 R5
+       * rgb1 = G5 B5 R6 G6 B6 R7 G7 B7 R8 G8 B8 R9 G9 B9 Ra Ga
+       * rgb2 = Ba Rb Gb Bb Rc Gc Bc Rd Gd Bd Re Ge Be Rf Gf Bf
+       *
+       * rgbg0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 G0 B1 G1 B2 G2 B3 G3
+       * rgbg1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 G4 B5 G5 B6 G6 B7 G7
+       * rgbg2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 G8 B9 G9 Ba Ga Bb Gb
+       * rgbg3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Gc Bd Gd Be Ge Bf Gf
+       */
+      rgbg0 = vec_perm(rgb0, rgb0, (__vector unsigned char)RGBG_INDEX0);
+      rgbg1 = vec_perm(rgb0, rgb1, (__vector unsigned char)RGBG_INDEX1);
+      rgbg2 = vec_perm(rgb1, rgb2, (__vector unsigned char)RGBG_INDEX2);
+      rgbg3 = vec_perm(rgb2, rgb2, (__vector unsigned char)RGBG_INDEX3);
+#else
+      /* Load 16 pixels == 64 bytes */
+      if ((size_t)inptr & 15) {
+        __vector unsigned char unaligned_shift_index;
+        rgb0 = vec_ld(0, inptr);
+        if (pitch > 16)
+          rgb1 = vec_ld(16, inptr);
+        else
+          rgb1 = vec_ld(-1, inptr + pitch);
+        if (pitch > 32)
+          rgb2 = vec_ld(32, inptr);
+        else
+          rgb2 = vec_ld(-1, inptr + pitch);
+        if (pitch > 48)
+          rgb3 = vec_ld(48, inptr);
+        else
+          rgb3 = vec_ld(-1, inptr + pitch);
+        if (pitch > 64)
+          rgb4 = vec_ld(64, inptr);
+        else
+          rgb4 = vec_ld(-1, inptr + pitch);
+        unaligned_shift_index = vec_lvsl(0, inptr);
+        rgb0 = vec_perm(rgb0, rgb1, unaligned_shift_index);
+        rgb1 = vec_perm(rgb1, rgb2, unaligned_shift_index);
+        rgb2 = vec_perm(rgb2, rgb3, unaligned_shift_index);
+        rgb3 = vec_perm(rgb3, rgb4, unaligned_shift_index);
+      } else {
+        rgb0 = vec_ld(0, inptr);
+        if (pitch > 16)
+          rgb1 = vec_ld(16, inptr);
+        if (pitch > 32)
+          rgb2 = vec_ld(32, inptr);
+        if (pitch > 48)
+          rgb3 = vec_ld(48, inptr);
+      }
+
+      /* rgb0 = R0 G0 B0 X0 R1 G1 B1 X1 R2 G2 B2 X2 R3 G3 B3 X3
+       * rgb0 = R4 G4 B4 X4 R5 G5 B5 X5 R6 G6 B6 X6 R7 G7 B7 X7
+       * rgb0 = R8 G8 B8 X8 R9 G9 B9 X9 Ra Ga Ba Xa Rb Gb Bb Xb
+       * rgb0 = Rc Gc Bc Xc Rd Gd Bd Xd Re Ge Be Xe Rf Gf Bf Xf
+       *
+       * rgbg0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 G0 B1 G1 B2 G2 B3 G3
+       * rgbg1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 G4 B5 G5 B6 G6 B7 G7
+       * rgbg2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 G8 B9 G9 Ba Ga Bb Gb
+       * rgbg3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Gc Bd Gd Be Ge Bf Gf
+       */
+      rgbg0 = vec_perm(rgb0, rgb0, (__vector unsigned char)RGBG_INDEX);
+      rgbg1 = vec_perm(rgb1, rgb1, (__vector unsigned char)RGBG_INDEX);
+      rgbg2 = vec_perm(rgb2, rgb2, (__vector unsigned char)RGBG_INDEX);
+      rgbg3 = vec_perm(rgb3, rgb3, (__vector unsigned char)RGBG_INDEX);
+#endif
+
+      /* rg0 = R0 G0 R1 G1 R2 G2 R3 G3
+       * bg0 = B0 G0 B1 G1 B2 G2 B3 G3
+       * ...
+       *
+       * NOTE: We have to use vec_merge*() here because vec_unpack*() doesn't
+       * support unsigned vectors.
+       */
+      rg0 = (__vector signed short)vec_mergeh(zero, rgbg0);
+      bg0 = (__vector signed short)vec_mergel(zero, rgbg0);
+      rg1 = (__vector signed short)vec_mergeh(zero, rgbg1);
+      bg1 = (__vector signed short)vec_mergel(zero, rgbg1);
+      rg2 = (__vector signed short)vec_mergeh(zero, rgbg2);
+      bg2 = (__vector signed short)vec_mergel(zero, rgbg2);
+      rg3 = (__vector signed short)vec_mergeh(zero, rgbg3);
+      bg3 = (__vector signed short)vec_mergel(zero, rgbg3);
+
+      /* (Original)
+       * Y  =  0.29900 * R + 0.58700 * G + 0.11400 * B
+       *
+       * (This implementation)
+       * Y  =  0.29900 * R + 0.33700 * G + 0.11400 * B + 0.25000 * G
+       */
+
+      /* Calculate Y values */
+
+      y0 = vec_msums(rg0, pw_f0299_f0337, pd_onehalf);
+      y1 = vec_msums(rg1, pw_f0299_f0337, pd_onehalf);
+      y2 = vec_msums(rg2, pw_f0299_f0337, pd_onehalf);
+      y3 = vec_msums(rg3, pw_f0299_f0337, pd_onehalf);
+      y0 = vec_msums(bg0, pw_f0114_f0250, y0);
+      y1 = vec_msums(bg1, pw_f0114_f0250, y1);
+      y2 = vec_msums(bg2, pw_f0114_f0250, y2);
+      y3 = vec_msums(bg3, pw_f0114_f0250, y3);
+      /* Clever way to avoid 4 shifts + 2 packs.  This packs the high word from
+       * each dword into a new 16-bit vector, which is the equivalent of
+       * descaling the 32-bit results (right-shifting by 16 bits) and then
+       * packing them.
+       */
+      y01 = vec_perm((__vector unsigned short)y0, (__vector unsigned short)y1,
+                     shift_pack_index);
+      y23 = vec_perm((__vector unsigned short)y2, (__vector unsigned short)y3,
+                     shift_pack_index);
+      y = vec_pack(y01, y23);
+      vec_st(y, 0, outptr);
+    }
+  }
+}
diff --git a/simd/jsimd.h b/simd/jsimd.h
index 9f41ef6..a8009b5 100644
--- a/simd/jsimd.h
+++ b/simd/jsimd.h
@@ -206,6 +206,28 @@
         (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
          JDIMENSION output_row, int num_rows);
 
+EXTERN(void) jsimd_rgb_gray_convert_altivec
+        (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+         JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extrgb_gray_convert_altivec
+        (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+         JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extrgbx_gray_convert_altivec
+        (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+         JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extbgr_gray_convert_altivec
+        (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+         JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extbgrx_gray_convert_altivec
+        (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+         JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extxbgr_gray_convert_altivec
+        (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+         JDIMENSION output_row, int num_rows);
+EXTERN(void) jsimd_extxrgb_gray_convert_altivec
+        (JDIMENSION img_width, JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+         JDIMENSION output_row, int num_rows);
+
 /* YCC --> RGB & extended RGB Colorspace Conversion */
 EXTERN(void) jsimd_ycc_rgb_convert_mmx
         (JDIMENSION out_width, JSAMPIMAGE input_buf, JDIMENSION input_row,
diff --git a/simd/jsimd_powerpc.c b/simd/jsimd_powerpc.c
index 6e6be26..a33bf62 100644
--- a/simd/jsimd_powerpc.c
+++ b/simd/jsimd_powerpc.c
@@ -61,6 +61,19 @@
 GLOBAL(int)
 jsimd_can_rgb_gray (void)
 {
+  init_simd();
+
+  /* The code is optimised for these values only */
+  if (BITS_IN_JSAMPLE != 8)
+    return 0;
+  if (sizeof(JDIMENSION) != 4)
+    return 0;
+  if ((RGB_PIXELSIZE != 3) && (RGB_PIXELSIZE != 4))
+    return 0;
+
+  if (simd_support & JSIMD_ALTIVEC)
+    return 1;
+
   return 0;
 }
 
@@ -119,6 +132,37 @@
                         JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
                         JDIMENSION output_row, int num_rows)
 {
+  void (*altivecfct)(JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
+
+  switch(cinfo->in_color_space) {
+    case JCS_EXT_RGB:
+      altivecfct=jsimd_extrgb_gray_convert_altivec;
+      break;
+    case JCS_EXT_RGBX:
+    case JCS_EXT_RGBA:
+      altivecfct=jsimd_extrgbx_gray_convert_altivec;
+      break;
+    case JCS_EXT_BGR:
+      altivecfct=jsimd_extbgr_gray_convert_altivec;
+      break;
+    case JCS_EXT_BGRX:
+    case JCS_EXT_BGRA:
+      altivecfct=jsimd_extbgrx_gray_convert_altivec;
+      break;
+    case JCS_EXT_XBGR:
+    case JCS_EXT_ABGR:
+      altivecfct=jsimd_extxbgr_gray_convert_altivec;
+      break;
+    case JCS_EXT_XRGB:
+    case JCS_EXT_ARGB:
+      altivecfct=jsimd_extxrgb_gray_convert_altivec;
+      break;
+    default:
+      altivecfct=jsimd_rgb_gray_convert_altivec;
+      break;
+  }
+
+  altivecfct(cinfo->image_width, input_buf, output_buf, output_row, num_rows);
 }
 
 GLOBAL(void)