Files
mozjpeg/simd/jdcolext-sse2.asm
DRC 123f7258a8 Format copyright headers more consistently
The IJG convention is to format copyright notices as:

Copyright (C) YYYY, Owner.

We try to maintain this convention for any code that is part of the
libjpeg API library (with the exception of preserving the copyright
notices from Cendio's code verbatim, since those predate
libjpeg-turbo.)

Note that the phrase "All Rights Reserved" is no longer necessary, since
all Buenos Aires Convention signatories signed onto the Berne Convention
in 2000.  However, our convention is to retain this phrase for any files
that have a self-contained copyright header but to leave it off of any
files that refer to another file for conditions of distribution and use.
For instance, all of the non-SIMD files in the libjpeg API library refer
to README.ijg, and the copyright message in that file contains "All
Rights Reserved", so it is unnecessary to add it to the individual
files.

The TurboJPEG code retains my preferred formatting convention for
copyright notices, which is based on that of VirtualGL (where the
TurboJPEG API originated.)
2016-05-28 19:16:58 -05:00

460 lines
18 KiB
NASM

;
; jdcolext.asm - colorspace conversion (SSE2)
;
; Copyright 2009, 2012 Pierre Ossman <ossman@cendio.se> for Cendio AB
; Copyright (C) 2012, D. R. Commander.
;
; Based on the 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