simd/jdclrss2.asm

;
; jdclrss2.asm - colorspace conversion (SSE2)
;
; Copyright 2009, 2012 Pierre Ossman <ossman@cendio.se> for Cendio AB
; Copyright 2012 D. R. Commander
;
; Based on
; x86 SIMD extension for IJG JPEG library
; Copyright (C) 1999-2006, MIYASAKA Masaru.
; For conditions of distribution and use, see copyright notice in jsimdext.inc
;
; This file should be assembled with NASM (Netwide Assembler),
; can *not* be assembled with Microsoft's MASM or any compatible
; assembler (including Borland's Turbo Assembler).
; NASM is available from http://nasm.sourceforge.net/ or
; http://sourceforge.net/project/showfiles.php?group_id=6208
;
; [TAB8]

%include "jcolsamp.inc"
				
; --------------------------------------------------------------------------
;
; Convert some rows of samples to the output colorspace.
;
; GLOBAL(void)
; jsimd_ycc_rgb_convert_sse2 (JDIMENSION out_width,
;                             JSAMPIMAGE input_buf, JDIMENSION input_row,
;                             JSAMPARRAY output_buf, int num_rows)
;

%define out_width(b)	(b)+8			; JDIMENSION out_width
%define input_buf(b)	(b)+12		; JSAMPIMAGE input_buf
%define input_row(b)	(b)+16		; JDIMENSION input_row
%define output_buf(b)	(b)+20		; JSAMPARRAY output_buf
%define num_rows(b)	(b)+24		; int num_rows

%define original_ebp	ebp+0
%define wk(i)		ebp-(WK_NUM-(i))*SIZEOF_XMMWORD	; xmmword wk[WK_NUM]
%define WK_NUM		2
%define gotptr		wk(0)-SIZEOF_POINTER	; void * gotptr

	align	16
	global	EXTN(jsimd_ycc_rgb_convert_sse2)

EXTN(jsimd_ycc_rgb_convert_sse2):
	push	ebp
	mov	eax,esp				; eax = original ebp
	sub	esp, byte 4
	and	esp, byte (-SIZEOF_XMMWORD)	; align to 128 bits
	mov	[esp],eax
	mov	ebp,esp				; ebp = aligned ebp
	lea	esp, [wk(0)]
	pushpic	eax		; make a room for GOT address
	push	ebx
;	push	ecx		; need not be preserved
;	push	edx		; need not be preserved
	push	esi
	push	edi

	get_GOT	ebx			; get GOT address
	movpic	POINTER [gotptr], ebx	; save GOT address

	mov	ecx, JDIMENSION [out_width(eax)]	; num_cols
	test	ecx,ecx
	jz	near .return

	push	ecx

	mov	edi, JSAMPIMAGE [input_buf(eax)]
	mov	ecx, JDIMENSION [input_row(eax)]
	mov	esi, JSAMPARRAY [edi+0*SIZEOF_JSAMPARRAY]
	mov	ebx, JSAMPARRAY [edi+1*SIZEOF_JSAMPARRAY]
	mov	edx, JSAMPARRAY [edi+2*SIZEOF_JSAMPARRAY]
	lea	esi, [esi+ecx*SIZEOF_JSAMPROW]
	lea	ebx, [ebx+ecx*SIZEOF_JSAMPROW]
	lea	edx, [edx+ecx*SIZEOF_JSAMPROW]

	pop	ecx

	mov	edi, JSAMPARRAY [output_buf(eax)]
	mov	eax, INT [num_rows(eax)]
	test	eax,eax
	jle	near .return
	alignx	16,7
.rowloop:
	push	eax
	push	edi
	push	edx
	push	ebx
	push	esi
	push	ecx			; col

	mov	esi, JSAMPROW [esi]	; inptr0
	mov	ebx, JSAMPROW [ebx]	; inptr1
	mov	edx, JSAMPROW [edx]	; inptr2
	mov	edi, JSAMPROW [edi]	; outptr
	movpic	eax, POINTER [gotptr]	; load GOT address (eax)
	alignx	16,7
.columnloop:

	movdqa	xmm5, XMMWORD [ebx]	; xmm5=Cb(0123456789ABCDEF)
	movdqa	xmm1, XMMWORD [edx]	; xmm1=Cr(0123456789ABCDEF)

	pcmpeqw	xmm4,xmm4
	pcmpeqw	xmm7,xmm7
	psrlw	xmm4,BYTE_BIT
	psllw	xmm7,7			; xmm7={0xFF80 0xFF80 0xFF80 0xFF80 ..}
	movdqa	xmm0,xmm4		; xmm0=xmm4={0xFF 0x00 0xFF 0x00 ..}

	pand	xmm4,xmm5		; xmm4=Cb(02468ACE)=CbE
	psrlw	xmm5,BYTE_BIT		; xmm5=Cb(13579BDF)=CbO
	pand	xmm0,xmm1		; xmm0=Cr(02468ACE)=CrE
	psrlw	xmm1,BYTE_BIT		; xmm1=Cr(13579BDF)=CrO

	paddw	xmm4,xmm7
	paddw	xmm5,xmm7
	paddw	xmm0,xmm7
	paddw	xmm1,xmm7

	; (Original)
	; R = Y                + 1.40200 * Cr
	; G = Y - 0.34414 * Cb - 0.71414 * Cr
	; B = Y + 1.77200 * Cb
	;
	; (This implementation)
	; R = Y                + 0.40200 * Cr + Cr
	; G = Y - 0.34414 * Cb + 0.28586 * Cr - Cr
	; B = Y - 0.22800 * Cb + Cb + Cb

	movdqa	xmm2,xmm4		; xmm2=CbE
	movdqa	xmm3,xmm5		; xmm3=CbO
	paddw	xmm4,xmm4		; xmm4=2*CbE
	paddw	xmm5,xmm5		; xmm5=2*CbO
	movdqa	xmm6,xmm0		; xmm6=CrE
	movdqa	xmm7,xmm1		; xmm7=CrO
	paddw	xmm0,xmm0		; xmm0=2*CrE
	paddw	xmm1,xmm1		; xmm1=2*CrO

	pmulhw	xmm4,[GOTOFF(eax,PW_MF0228)]	; xmm4=(2*CbE * -FIX(0.22800))
	pmulhw	xmm5,[GOTOFF(eax,PW_MF0228)]	; xmm5=(2*CbO * -FIX(0.22800))
	pmulhw	xmm0,[GOTOFF(eax,PW_F0402)]	; xmm0=(2*CrE * FIX(0.40200))
	pmulhw	xmm1,[GOTOFF(eax,PW_F0402)]	; xmm1=(2*CrO * FIX(0.40200))

	paddw	xmm4,[GOTOFF(eax,PW_ONE)]
	paddw	xmm5,[GOTOFF(eax,PW_ONE)]
	psraw	xmm4,1			; xmm4=(CbE * -FIX(0.22800))
	psraw	xmm5,1			; xmm5=(CbO * -FIX(0.22800))
	paddw	xmm0,[GOTOFF(eax,PW_ONE)]
	paddw	xmm1,[GOTOFF(eax,PW_ONE)]
	psraw	xmm0,1			; xmm0=(CrE * FIX(0.40200))
	psraw	xmm1,1			; xmm1=(CrO * FIX(0.40200))

	paddw	xmm4,xmm2
	paddw	xmm5,xmm3
	paddw	xmm4,xmm2		; xmm4=(CbE * FIX(1.77200))=(B-Y)E
	paddw	xmm5,xmm3		; xmm5=(CbO * FIX(1.77200))=(B-Y)O
	paddw	xmm0,xmm6		; xmm0=(CrE * FIX(1.40200))=(R-Y)E
	paddw	xmm1,xmm7		; xmm1=(CrO * FIX(1.40200))=(R-Y)O

	movdqa	XMMWORD [wk(0)], xmm4	; wk(0)=(B-Y)E
	movdqa	XMMWORD [wk(1)], xmm5	; wk(1)=(B-Y)O

	movdqa    xmm4,xmm2
	movdqa    xmm5,xmm3
	punpcklwd xmm2,xmm6
	punpckhwd xmm4,xmm6
	pmaddwd   xmm2,[GOTOFF(eax,PW_MF0344_F0285)]
	pmaddwd   xmm4,[GOTOFF(eax,PW_MF0344_F0285)]
	punpcklwd xmm3,xmm7
	punpckhwd xmm5,xmm7
	pmaddwd   xmm3,[GOTOFF(eax,PW_MF0344_F0285)]
	pmaddwd   xmm5,[GOTOFF(eax,PW_MF0344_F0285)]

	paddd     xmm2,[GOTOFF(eax,PD_ONEHALF)]
	paddd     xmm4,[GOTOFF(eax,PD_ONEHALF)]
	psrad     xmm2,SCALEBITS
	psrad     xmm4,SCALEBITS
	paddd     xmm3,[GOTOFF(eax,PD_ONEHALF)]
	paddd     xmm5,[GOTOFF(eax,PD_ONEHALF)]
	psrad     xmm3,SCALEBITS
	psrad     xmm5,SCALEBITS

	packssdw  xmm2,xmm4	; xmm2=CbE*-FIX(0.344)+CrE*FIX(0.285)
	packssdw  xmm3,xmm5	; xmm3=CbO*-FIX(0.344)+CrO*FIX(0.285)
	psubw     xmm2,xmm6	; xmm2=CbE*-FIX(0.344)+CrE*-FIX(0.714)=(G-Y)E
	psubw     xmm3,xmm7	; xmm3=CbO*-FIX(0.344)+CrO*-FIX(0.714)=(G-Y)O

	movdqa    xmm5, XMMWORD [esi]	; xmm5=Y(0123456789ABCDEF)

	pcmpeqw   xmm4,xmm4
	psrlw     xmm4,BYTE_BIT		; xmm4={0xFF 0x00 0xFF 0x00 ..}
	pand      xmm4,xmm5		; xmm4=Y(02468ACE)=YE
	psrlw     xmm5,BYTE_BIT		; xmm5=Y(13579BDF)=YO

	paddw     xmm0,xmm4		; xmm0=((R-Y)E+YE)=RE=R(02468ACE)
	paddw     xmm1,xmm5		; xmm1=((R-Y)O+YO)=RO=R(13579BDF)
	packuswb  xmm0,xmm0		; xmm0=R(02468ACE********)
	packuswb  xmm1,xmm1		; xmm1=R(13579BDF********)

	paddw     xmm2,xmm4		; xmm2=((G-Y)E+YE)=GE=G(02468ACE)
	paddw     xmm3,xmm5		; xmm3=((G-Y)O+YO)=GO=G(13579BDF)
	packuswb  xmm2,xmm2		; xmm2=G(02468ACE********)
	packuswb  xmm3,xmm3		; xmm3=G(13579BDF********)

	paddw     xmm4, XMMWORD [wk(0)]	; xmm4=(YE+(B-Y)E)=BE=B(02468ACE)
	paddw     xmm5, XMMWORD [wk(1)]	; xmm5=(YO+(B-Y)O)=BO=B(13579BDF)
	packuswb  xmm4,xmm4		; xmm4=B(02468ACE********)
	packuswb  xmm5,xmm5		; xmm5=B(13579BDF********)

%if RGB_PIXELSIZE == 3 ; ---------------

	; xmmA=(00 02 04 06 08 0A 0C 0E **), xmmB=(01 03 05 07 09 0B 0D 0F **)
	; xmmC=(10 12 14 16 18 1A 1C 1E **), xmmD=(11 13 15 17 19 1B 1D 1F **)
	; xmmE=(20 22 24 26 28 2A 2C 2E **), xmmF=(21 23 25 27 29 2B 2D 2F **)
	; xmmG=(** ** ** ** ** ** ** ** **), xmmH=(** ** ** ** ** ** ** ** **)

	punpcklbw xmmA,xmmC	; xmmA=(00 10 02 12 04 14 06 16 08 18 0A 1A 0C 1C 0E 1E)
	punpcklbw xmmE,xmmB	; xmmE=(20 01 22 03 24 05 26 07 28 09 2A 0B 2C 0D 2E 0F)
	punpcklbw xmmD,xmmF	; xmmD=(11 21 13 23 15 25 17 27 19 29 1B 2B 1D 2D 1F 2F)

	movdqa    xmmG,xmmA
	movdqa    xmmH,xmmA
	punpcklwd xmmA,xmmE	; xmmA=(00 10 20 01 02 12 22 03 04 14 24 05 06 16 26 07)
	punpckhwd xmmG,xmmE	; xmmG=(08 18 28 09 0A 1A 2A 0B 0C 1C 2C 0D 0E 1E 2E 0F)

	psrldq    xmmH,2	; xmmH=(02 12 04 14 06 16 08 18 0A 1A 0C 1C 0E 1E -- --)
	psrldq    xmmE,2	; xmmE=(22 03 24 05 26 07 28 09 2A 0B 2C 0D 2E 0F -- --)

	movdqa    xmmC,xmmD
	movdqa    xmmB,xmmD
	punpcklwd xmmD,xmmH	; xmmD=(11 21 02 12 13 23 04 14 15 25 06 16 17 27 08 18)
	punpckhwd xmmC,xmmH	; xmmC=(19 29 0A 1A 1B 2B 0C 1C 1D 2D 0E 1E 1F 2F -- --)

	psrldq    xmmB,2	; xmmB=(13 23 15 25 17 27 19 29 1B 2B 1D 2D 1F 2F -- --)

	movdqa    xmmF,xmmE
	punpcklwd xmmE,xmmB	; xmmE=(22 03 13 23 24 05 15 25 26 07 17 27 28 09 19 29)
	punpckhwd xmmF,xmmB	; xmmF=(2A 0B 1B 2B 2C 0D 1D 2D 2E 0F 1F 2F -- -- -- --)

	pshufd    xmmH,xmmA,0x4E; xmmH=(04 14 24 05 06 16 26 07 00 10 20 01 02 12 22 03)
	movdqa    xmmB,xmmE
	punpckldq xmmA,xmmD	; xmmA=(00 10 20 01 11 21 02 12 02 12 22 03 13 23 04 14)
	punpckldq xmmE,xmmH	; xmmE=(22 03 13 23 04 14 24 05 24 05 15 25 06 16 26 07)
	punpckhdq xmmD,xmmB	; xmmD=(15 25 06 16 26 07 17 27 17 27 08 18 28 09 19 29)

	pshufd    xmmH,xmmG,0x4E; xmmH=(0C 1C 2C 0D 0E 1E 2E 0F 08 18 28 09 0A 1A 2A 0B)
	movdqa    xmmB,xmmF
	punpckldq xmmG,xmmC	; xmmG=(08 18 28 09 19 29 0A 1A 0A 1A 2A 0B 1B 2B 0C 1C)
	punpckldq xmmF,xmmH	; xmmF=(2A 0B 1B 2B 0C 1C 2C 0D 2C 0D 1D 2D 0E 1E 2E 0F)
	punpckhdq xmmC,xmmB	; xmmC=(1D 2D 0E 1E 2E 0F 1F 2F 1F 2F -- -- -- -- -- --)

	punpcklqdq xmmA,xmmE	; xmmA=(00 10 20 01 11 21 02 12 22 03 13 23 04 14 24 05)
	punpcklqdq xmmD,xmmG	; xmmD=(15 25 06 16 26 07 17 27 08 18 28 09 19 29 0A 1A)
	punpcklqdq xmmF,xmmC	; xmmF=(2A 0B 1B 2B 0C 1C 2C 0D 1D 2D 0E 1E 2E 0F 1F 2F)

	cmp	ecx, byte SIZEOF_XMMWORD
	jb	short .column_st32

	test	edi, SIZEOF_XMMWORD-1
	jnz	short .out1
	; --(aligned)-------------------
	movntdq	XMMWORD [edi+0*SIZEOF_XMMWORD], xmmA
	movntdq	XMMWORD [edi+1*SIZEOF_XMMWORD], xmmD
	movntdq	XMMWORD [edi+2*SIZEOF_XMMWORD], xmmF
	jmp	short .out0
.out1:	; --(unaligned)-----------------
	movdqu	XMMWORD [edi+0*SIZEOF_XMMWORD], xmmA
	movdqu	XMMWORD [edi+1*SIZEOF_XMMWORD], xmmD
	movdqu	XMMWORD [edi+2*SIZEOF_XMMWORD], xmmF
.out0:
	add	edi, byte RGB_PIXELSIZE*SIZEOF_XMMWORD	; outptr
	sub	ecx, byte SIZEOF_XMMWORD
	jz	near .nextrow

	add	esi, byte SIZEOF_XMMWORD	; inptr0
	add	ebx, byte SIZEOF_XMMWORD	; inptr1
	add	edx, byte SIZEOF_XMMWORD	; inptr2
	jmp	near .columnloop
	alignx	16,7

.column_st32:
	lea	ecx, [ecx+ecx*2]		; imul ecx, RGB_PIXELSIZE
	cmp	ecx, byte 2*SIZEOF_XMMWORD
	jb	short .column_st16
	movdqu	XMMWORD [edi+0*SIZEOF_XMMWORD], xmmA
	movdqu	XMMWORD [edi+1*SIZEOF_XMMWORD], xmmD
	add	edi, byte 2*SIZEOF_XMMWORD	; outptr
	movdqa	xmmA,xmmF
	sub	ecx, byte 2*SIZEOF_XMMWORD
	jmp	short .column_st15
.column_st16:
	cmp	ecx, byte SIZEOF_XMMWORD
	jb	short .column_st15
	movdqu	XMMWORD [edi+0*SIZEOF_XMMWORD], xmmA
	add	edi, byte SIZEOF_XMMWORD	; outptr
	movdqa	xmmA,xmmD
	sub	ecx, byte SIZEOF_XMMWORD
.column_st15:
	; Store the lower 8 bytes of xmmA to the output when it has enough
	; space.
	cmp	ecx, byte SIZEOF_MMWORD
	jb	short .column_st7
	movq	XMM_MMWORD [edi], xmmA
	add	edi, byte SIZEOF_MMWORD
	sub	ecx, byte SIZEOF_MMWORD
	psrldq	xmmA, SIZEOF_MMWORD
.column_st7:
	; Store the lower 4 bytes of xmmA to the output when it has enough
	; space.
	cmp	ecx, byte SIZEOF_DWORD
	jb	short .column_st3
	movd	XMM_DWORD [edi], xmmA
	add	edi, byte SIZEOF_DWORD
	sub	ecx, byte SIZEOF_DWORD
	psrldq	xmmA, SIZEOF_DWORD
.column_st3:
	; Store the lower 2 bytes of eax to the output when it has enough
	; space.
	movd	eax, xmmA
	cmp	ecx, byte SIZEOF_WORD
	jb	short .column_st1
	mov	WORD [edi], ax
	add	edi, byte SIZEOF_WORD
	sub	ecx, byte SIZEOF_WORD
	shr	eax, 16
.column_st1:
	; Store the lower 1 byte of eax to the output when it has enough
	; space.
	test	ecx, ecx
	jz	short .nextrow
	mov	BYTE [edi], al

%else ; RGB_PIXELSIZE == 4 ; -----------

%ifdef RGBX_FILLER_0XFF
	pcmpeqb   xmm6,xmm6		; xmm6=XE=X(02468ACE********)
	pcmpeqb   xmm7,xmm7		; xmm7=XO=X(13579BDF********)
%else
	pxor      xmm6,xmm6		; xmm6=XE=X(02468ACE********)
	pxor      xmm7,xmm7		; xmm7=XO=X(13579BDF********)
%endif
	; xmmA=(00 02 04 06 08 0A 0C 0E **), xmmB=(01 03 05 07 09 0B 0D 0F **)
	; xmmC=(10 12 14 16 18 1A 1C 1E **), xmmD=(11 13 15 17 19 1B 1D 1F **)
	; xmmE=(20 22 24 26 28 2A 2C 2E **), xmmF=(21 23 25 27 29 2B 2D 2F **)
	; xmmG=(30 32 34 36 38 3A 3C 3E **), xmmH=(31 33 35 37 39 3B 3D 3F **)

	punpcklbw xmmA,xmmC	; xmmA=(00 10 02 12 04 14 06 16 08 18 0A 1A 0C 1C 0E 1E)
	punpcklbw xmmE,xmmG	; xmmE=(20 30 22 32 24 34 26 36 28 38 2A 3A 2C 3C 2E 3E)
	punpcklbw xmmB,xmmD	; xmmB=(01 11 03 13 05 15 07 17 09 19 0B 1B 0D 1D 0F 1F)
	punpcklbw xmmF,xmmH	; xmmF=(21 31 23 33 25 35 27 37 29 39 2B 3B 2D 3D 2F 3F)

	movdqa    xmmC,xmmA
	punpcklwd xmmA,xmmE	; xmmA=(00 10 20 30 02 12 22 32 04 14 24 34 06 16 26 36)
	punpckhwd xmmC,xmmE	; xmmC=(08 18 28 38 0A 1A 2A 3A 0C 1C 2C 3C 0E 1E 2E 3E)
	movdqa    xmmG,xmmB
	punpcklwd xmmB,xmmF	; xmmB=(01 11 21 31 03 13 23 33 05 15 25 35 07 17 27 37)
	punpckhwd xmmG,xmmF	; xmmG=(09 19 29 39 0B 1B 2B 3B 0D 1D 2D 3D 0F 1F 2F 3F)

	movdqa    xmmD,xmmA
	punpckldq xmmA,xmmB	; xmmA=(00 10 20 30 01 11 21 31 02 12 22 32 03 13 23 33)
	punpckhdq xmmD,xmmB	; xmmD=(04 14 24 34 05 15 25 35 06 16 26 36 07 17 27 37)
	movdqa    xmmH,xmmC
	punpckldq xmmC,xmmG	; xmmC=(08 18 28 38 09 19 29 39 0A 1A 2A 3A 0B 1B 2B 3B)
	punpckhdq xmmH,xmmG	; xmmH=(0C 1C 2C 3C 0D 1D 2D 3D 0E 1E 2E 3E 0F 1F 2F 3F)

	cmp	ecx, byte SIZEOF_XMMWORD
	jb	short .column_st32

	test	edi, SIZEOF_XMMWORD-1
	jnz	short .out1
	; --(aligned)-------------------
	movntdq	XMMWORD [edi+0*SIZEOF_XMMWORD], xmmA
	movntdq	XMMWORD [edi+1*SIZEOF_XMMWORD], xmmD
	movntdq	XMMWORD [edi+2*SIZEOF_XMMWORD], xmmC
	movntdq	XMMWORD [edi+3*SIZEOF_XMMWORD], xmmH
	jmp	short .out0
.out1:	; --(unaligned)-----------------
	movdqu	XMMWORD [edi+0*SIZEOF_XMMWORD], xmmA
	movdqu	XMMWORD [edi+1*SIZEOF_XMMWORD], xmmD
	movdqu	XMMWORD [edi+2*SIZEOF_XMMWORD], xmmC
	movdqu	XMMWORD [edi+3*SIZEOF_XMMWORD], xmmH
.out0:
	add	edi, byte RGB_PIXELSIZE*SIZEOF_XMMWORD	; outptr
	sub	ecx, byte SIZEOF_XMMWORD
	jz	near .nextrow

	add	esi, byte SIZEOF_XMMWORD	; inptr0
	add	ebx, byte SIZEOF_XMMWORD	; inptr1
	add	edx, byte SIZEOF_XMMWORD	; inptr2
	jmp	near .columnloop
	alignx	16,7

.column_st32:
	cmp	ecx, byte SIZEOF_XMMWORD/2
	jb	short .column_st16
	movdqu	XMMWORD [edi+0*SIZEOF_XMMWORD], xmmA
	movdqu	XMMWORD [edi+1*SIZEOF_XMMWORD], xmmD
	add	edi, byte 2*SIZEOF_XMMWORD	; outptr
	movdqa	xmmA,xmmC
	movdqa	xmmD,xmmH
	sub	ecx, byte SIZEOF_XMMWORD/2
.column_st16:
	cmp	ecx, byte SIZEOF_XMMWORD/4
	jb	short .column_st15
	movdqu	XMMWORD [edi+0*SIZEOF_XMMWORD], xmmA
	add	edi, byte SIZEOF_XMMWORD	; outptr
	movdqa	xmmA,xmmD
	sub	ecx, byte SIZEOF_XMMWORD/4
.column_st15:
	; Store two pixels (8 bytes) of xmmA to the output when it has enough
	; space.
	cmp	ecx, byte SIZEOF_XMMWORD/8
	jb	short .column_st7
	movq	XMM_MMWORD [edi], xmmA
	add	edi, byte SIZEOF_XMMWORD/8*4
	sub	ecx, byte SIZEOF_XMMWORD/8
	psrldq	xmmA, SIZEOF_XMMWORD/8*4
.column_st7:
	; Store one pixel (4 bytes) of xmmA to the output when it has enough
	; space.
	test	ecx, ecx
	jz	short .nextrow
	movd	XMM_DWORD [edi], xmmA

%endif ; RGB_PIXELSIZE ; ---------------

	alignx	16,7

.nextrow:
	pop	ecx
	pop	esi
	pop	ebx
	pop	edx
	pop	edi
	pop	eax

	add	esi, byte SIZEOF_JSAMPROW
	add	ebx, byte SIZEOF_JSAMPROW
	add	edx, byte SIZEOF_JSAMPROW
	add	edi, byte SIZEOF_JSAMPROW	; output_buf
	dec	eax				; num_rows
	jg	near .rowloop

	sfence		; flush the write buffer

.return:
	pop	edi
	pop	esi
;	pop	edx		; need not be preserved
;	pop	ecx		; need not be preserved
	pop	ebx
	mov	esp,ebp		; esp <- aligned ebp
	pop	esp		; esp <- original ebp
	pop	ebp
	ret

; For some reason, the OS X linker does not honor the request to align the
; segment unless we do this.
	align	16