; ; jcclrss2.asm - colorspace conversion (SSE2) ; ; 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_rgb_ycc_convert_sse2 (JDIMENSION img_width, ; JSAMPARRAY input_buf, JSAMPIMAGE output_buf, ; JDIMENSION output_row, int num_rows); ; %define img_width(b) (b)+8 ; JDIMENSION img_width %define input_buf(b) (b)+12 ; JSAMPARRAY input_buf %define output_buf(b) (b)+16 ; JSAMPIMAGE output_buf %define output_row(b) (b)+20 ; JDIMENSION output_row %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 8 %define gotptr wk(0)-SIZEOF_POINTER ; void * gotptr align 16 global EXTN(jsimd_rgb_ycc_convert_sse2) PRIVATE EXTN(jsimd_rgb_ycc_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 [img_width(eax)] test ecx,ecx jz near .return push ecx mov esi, JSAMPIMAGE [output_buf(eax)] mov ecx, JDIMENSION [output_row(eax)] mov edi, JSAMPARRAY [esi+0*SIZEOF_JSAMPARRAY] mov ebx, JSAMPARRAY [esi+1*SIZEOF_JSAMPARRAY] mov edx, JSAMPARRAY [esi+2*SIZEOF_JSAMPARRAY] lea edi, [edi+ecx*SIZEOF_JSAMPROW] lea ebx, [ebx+ecx*SIZEOF_JSAMPROW] lea edx, [edx+ecx*SIZEOF_JSAMPROW] pop ecx mov esi, JSAMPARRAY [input_buf(eax)] mov eax, INT [num_rows(eax)] test eax,eax jle near .return alignx 16,7 .rowloop: pushpic eax push edx push ebx push edi push esi push ecx ; col mov esi, JSAMPROW [esi] ; inptr mov edi, JSAMPROW [edi] ; outptr0 mov ebx, JSAMPROW [ebx] ; outptr1 mov edx, JSAMPROW [edx] ; outptr2 movpic eax, POINTER [gotptr] ; load GOT address (eax) cmp ecx, byte SIZEOF_XMMWORD jae near .columnloop alignx 16,7 %if RGB_PIXELSIZE == 3 ; --------------- .column_ld1: push eax push edx lea ecx,[ecx+ecx*2] ; imul ecx,RGB_PIXELSIZE test cl, SIZEOF_BYTE jz short .column_ld2 sub ecx, byte SIZEOF_BYTE movzx eax, BYTE [esi+ecx] .column_ld2: test cl, SIZEOF_WORD jz short .column_ld4 sub ecx, byte SIZEOF_WORD movzx edx, WORD [esi+ecx] shl eax, WORD_BIT or eax,edx .column_ld4: movd xmmA,eax pop edx pop eax test cl, SIZEOF_DWORD jz short .column_ld8 sub ecx, byte SIZEOF_DWORD movd xmmF, XMM_DWORD [esi+ecx] pslldq xmmA, SIZEOF_DWORD por xmmA,xmmF .column_ld8: test cl, SIZEOF_MMWORD jz short .column_ld16 sub ecx, byte SIZEOF_MMWORD movq xmmB, XMM_MMWORD [esi+ecx] pslldq xmmA, SIZEOF_MMWORD por xmmA,xmmB .column_ld16: test cl, SIZEOF_XMMWORD jz short .column_ld32 movdqa xmmF,xmmA movdqu xmmA, XMMWORD [esi+0*SIZEOF_XMMWORD] mov ecx, SIZEOF_XMMWORD jmp short .rgb_ycc_cnv .column_ld32: test cl, 2*SIZEOF_XMMWORD mov ecx, SIZEOF_XMMWORD jz short .rgb_ycc_cnv movdqa xmmB,xmmA movdqu xmmA, XMMWORD [esi+0*SIZEOF_XMMWORD] movdqu xmmF, XMMWORD [esi+1*SIZEOF_XMMWORD] jmp short .rgb_ycc_cnv alignx 16,7 .columnloop: movdqu xmmA, XMMWORD [esi+0*SIZEOF_XMMWORD] movdqu xmmF, XMMWORD [esi+1*SIZEOF_XMMWORD] movdqu xmmB, XMMWORD [esi+2*SIZEOF_XMMWORD] .rgb_ycc_cnv: ; xmmA=(00 10 20 01 11 21 02 12 22 03 13 23 04 14 24 05) ; xmmF=(15 25 06 16 26 07 17 27 08 18 28 09 19 29 0A 1A) ; xmmB=(2A 0B 1B 2B 0C 1C 2C 0D 1D 2D 0E 1E 2E 0F 1F 2F) movdqa xmmG,xmmA pslldq xmmA,8 ; xmmA=(-- -- -- -- -- -- -- -- 00 10 20 01 11 21 02 12) psrldq xmmG,8 ; xmmG=(22 03 13 23 04 14 24 05 -- -- -- -- -- -- -- --) punpckhbw xmmA,xmmF ; xmmA=(00 08 10 18 20 28 01 09 11 19 21 29 02 0A 12 1A) pslldq xmmF,8 ; xmmF=(-- -- -- -- -- -- -- -- 15 25 06 16 26 07 17 27) punpcklbw xmmG,xmmB ; xmmG=(22 2A 03 0B 13 1B 23 2B 04 0C 14 1C 24 2C 05 0D) punpckhbw xmmF,xmmB ; xmmF=(15 1D 25 2D 06 0E 16 1E 26 2E 07 0F 17 1F 27 2F) movdqa xmmD,xmmA pslldq xmmA,8 ; xmmA=(-- -- -- -- -- -- -- -- 00 08 10 18 20 28 01 09) psrldq xmmD,8 ; xmmD=(11 19 21 29 02 0A 12 1A -- -- -- -- -- -- -- --) punpckhbw xmmA,xmmG ; xmmA=(00 04 08 0C 10 14 18 1C 20 24 28 2C 01 05 09 0D) pslldq xmmG,8 ; xmmG=(-- -- -- -- -- -- -- -- 22 2A 03 0B 13 1B 23 2B) punpcklbw xmmD,xmmF ; xmmD=(11 15 19 1D 21 25 29 2D 02 06 0A 0E 12 16 1A 1E) punpckhbw xmmG,xmmF ; xmmG=(22 26 2A 2E 03 07 0B 0F 13 17 1B 1F 23 27 2B 2F) movdqa xmmE,xmmA pslldq xmmA,8 ; xmmA=(-- -- -- -- -- -- -- -- 00 04 08 0C 10 14 18 1C) psrldq xmmE,8 ; xmmE=(20 24 28 2C 01 05 09 0D -- -- -- -- -- -- -- --) punpckhbw xmmA,xmmD ; xmmA=(00 02 04 06 08 0A 0C 0E 10 12 14 16 18 1A 1C 1E) pslldq xmmD,8 ; xmmD=(-- -- -- -- -- -- -- -- 11 15 19 1D 21 25 29 2D) punpcklbw xmmE,xmmG ; xmmE=(20 22 24 26 28 2A 2C 2E 01 03 05 07 09 0B 0D 0F) punpckhbw xmmD,xmmG ; xmmD=(11 13 15 17 19 1B 1D 1F 21 23 25 27 29 2B 2D 2F) pxor xmmH,xmmH movdqa xmmC,xmmA punpcklbw xmmA,xmmH ; xmmA=(00 02 04 06 08 0A 0C 0E) punpckhbw xmmC,xmmH ; xmmC=(10 12 14 16 18 1A 1C 1E) movdqa xmmB,xmmE punpcklbw xmmE,xmmH ; xmmE=(20 22 24 26 28 2A 2C 2E) punpckhbw xmmB,xmmH ; xmmB=(01 03 05 07 09 0B 0D 0F) movdqa xmmF,xmmD punpcklbw xmmD,xmmH ; xmmD=(11 13 15 17 19 1B 1D 1F) punpckhbw xmmF,xmmH ; xmmF=(21 23 25 27 29 2B 2D 2F) %else ; RGB_PIXELSIZE == 4 ; ----------- .column_ld1: test cl, SIZEOF_XMMWORD/16 jz short .column_ld2 sub ecx, byte SIZEOF_XMMWORD/16 movd xmmA, XMM_DWORD [esi+ecx*RGB_PIXELSIZE] .column_ld2: test cl, SIZEOF_XMMWORD/8 jz short .column_ld4 sub ecx, byte SIZEOF_XMMWORD/8 movq xmmE, XMM_MMWORD [esi+ecx*RGB_PIXELSIZE] pslldq xmmA, SIZEOF_MMWORD por xmmA,xmmE .column_ld4: test cl, SIZEOF_XMMWORD/4 jz short .column_ld8 sub ecx, byte SIZEOF_XMMWORD/4 movdqa xmmE,xmmA movdqu xmmA, XMMWORD [esi+ecx*RGB_PIXELSIZE] .column_ld8: test cl, SIZEOF_XMMWORD/2 mov ecx, SIZEOF_XMMWORD jz short .rgb_ycc_cnv movdqa xmmF,xmmA movdqa xmmH,xmmE movdqu xmmA, XMMWORD [esi+0*SIZEOF_XMMWORD] movdqu xmmE, XMMWORD [esi+1*SIZEOF_XMMWORD] jmp short .rgb_ycc_cnv alignx 16,7 .columnloop: movdqu xmmA, XMMWORD [esi+0*SIZEOF_XMMWORD] movdqu xmmE, XMMWORD [esi+1*SIZEOF_XMMWORD] movdqu xmmF, XMMWORD [esi+2*SIZEOF_XMMWORD] movdqu xmmH, XMMWORD [esi+3*SIZEOF_XMMWORD] .rgb_ycc_cnv: ; xmmA=(00 10 20 30 01 11 21 31 02 12 22 32 03 13 23 33) ; xmmE=(04 14 24 34 05 15 25 35 06 16 26 36 07 17 27 37) ; xmmF=(08 18 28 38 09 19 29 39 0A 1A 2A 3A 0B 1B 2B 3B) ; xmmH=(0C 1C 2C 3C 0D 1D 2D 3D 0E 1E 2E 3E 0F 1F 2F 3F) movdqa xmmD,xmmA punpcklbw xmmA,xmmE ; xmmA=(00 04 10 14 20 24 30 34 01 05 11 15 21 25 31 35) punpckhbw xmmD,xmmE ; xmmD=(02 06 12 16 22 26 32 36 03 07 13 17 23 27 33 37) movdqa xmmC,xmmF punpcklbw xmmF,xmmH ; xmmF=(08 0C 18 1C 28 2C 38 3C 09 0D 19 1D 29 2D 39 3D) punpckhbw xmmC,xmmH ; xmmC=(0A 0E 1A 1E 2A 2E 3A 3E 0B 0F 1B 1F 2B 2F 3B 3F) movdqa xmmB,xmmA punpcklwd xmmA,xmmF ; xmmA=(00 04 08 0C 10 14 18 1C 20 24 28 2C 30 34 38 3C) punpckhwd xmmB,xmmF ; xmmB=(01 05 09 0D 11 15 19 1D 21 25 29 2D 31 35 39 3D) movdqa xmmG,xmmD punpcklwd xmmD,xmmC ; xmmD=(02 06 0A 0E 12 16 1A 1E 22 26 2A 2E 32 36 3A 3E) punpckhwd xmmG,xmmC ; xmmG=(03 07 0B 0F 13 17 1B 1F 23 27 2B 2F 33 37 3B 3F) movdqa xmmE,xmmA punpcklbw xmmA,xmmD ; xmmA=(00 02 04 06 08 0A 0C 0E 10 12 14 16 18 1A 1C 1E) punpckhbw xmmE,xmmD ; xmmE=(20 22 24 26 28 2A 2C 2E 30 32 34 36 38 3A 3C 3E) movdqa xmmH,xmmB punpcklbw xmmB,xmmG ; xmmB=(01 03 05 07 09 0B 0D 0F 11 13 15 17 19 1B 1D 1F) punpckhbw xmmH,xmmG ; xmmH=(21 23 25 27 29 2B 2D 2F 31 33 35 37 39 3B 3D 3F) pxor xmmF,xmmF movdqa xmmC,xmmA punpcklbw xmmA,xmmF ; xmmA=(00 02 04 06 08 0A 0C 0E) punpckhbw xmmC,xmmF ; xmmC=(10 12 14 16 18 1A 1C 1E) movdqa xmmD,xmmB punpcklbw xmmB,xmmF ; xmmB=(01 03 05 07 09 0B 0D 0F) punpckhbw xmmD,xmmF ; xmmD=(11 13 15 17 19 1B 1D 1F) movdqa xmmG,xmmE punpcklbw xmmE,xmmF ; xmmE=(20 22 24 26 28 2A 2C 2E) punpckhbw xmmG,xmmF ; xmmG=(30 32 34 36 38 3A 3C 3E) punpcklbw xmmF,xmmH punpckhbw xmmH,xmmH psrlw xmmF,BYTE_BIT ; xmmF=(21 23 25 27 29 2B 2D 2F) psrlw xmmH,BYTE_BIT ; xmmH=(31 33 35 37 39 3B 3D 3F) %endif ; RGB_PIXELSIZE ; --------------- ; xmm0=R(02468ACE)=RE, xmm2=G(02468ACE)=GE, xmm4=B(02468ACE)=BE ; xmm1=R(13579BDF)=RO, xmm3=G(13579BDF)=GO, xmm5=B(13579BDF)=BO ; (Original) ; Y = 0.29900 * R + 0.58700 * G + 0.11400 * B ; Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + CENTERJSAMPLE ; Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + CENTERJSAMPLE ; ; (This implementation) ; Y = 0.29900 * R + 0.33700 * G + 0.11400 * B + 0.25000 * G ; Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + CENTERJSAMPLE ; Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + CENTERJSAMPLE movdqa XMMWORD [wk(0)], xmm0 ; wk(0)=RE movdqa XMMWORD [wk(1)], xmm1 ; wk(1)=RO movdqa XMMWORD [wk(2)], xmm4 ; wk(2)=BE movdqa XMMWORD [wk(3)], xmm5 ; wk(3)=BO movdqa xmm6,xmm1 punpcklwd xmm1,xmm3 punpckhwd xmm6,xmm3 movdqa xmm7,xmm1 movdqa xmm4,xmm6 pmaddwd xmm1,[GOTOFF(eax,PW_F0299_F0337)] ; xmm1=ROL*FIX(0.299)+GOL*FIX(0.337) pmaddwd xmm6,[GOTOFF(eax,PW_F0299_F0337)] ; xmm6=ROH*FIX(0.299)+GOH*FIX(0.337) pmaddwd xmm7,[GOTOFF(eax,PW_MF016_MF033)] ; xmm7=ROL*-FIX(0.168)+GOL*-FIX(0.331) pmaddwd xmm4,[GOTOFF(eax,PW_MF016_MF033)] ; xmm4=ROH*-FIX(0.168)+GOH*-FIX(0.331) movdqa XMMWORD [wk(4)], xmm1 ; wk(4)=ROL*FIX(0.299)+GOL*FIX(0.337) movdqa XMMWORD [wk(5)], xmm6 ; wk(5)=ROH*FIX(0.299)+GOH*FIX(0.337) pxor xmm1,xmm1 pxor xmm6,xmm6 punpcklwd xmm1,xmm5 ; xmm1=BOL punpckhwd xmm6,xmm5 ; xmm6=BOH psrld xmm1,1 ; xmm1=BOL*FIX(0.500) psrld xmm6,1 ; xmm6=BOH*FIX(0.500) movdqa xmm5,[GOTOFF(eax,PD_ONEHALFM1_CJ)] ; xmm5=[PD_ONEHALFM1_CJ] paddd xmm7,xmm1 paddd xmm4,xmm6 paddd xmm7,xmm5 paddd xmm4,xmm5 psrld xmm7,SCALEBITS ; xmm7=CbOL psrld xmm4,SCALEBITS ; xmm4=CbOH packssdw xmm7,xmm4 ; xmm7=CbO movdqa xmm1, XMMWORD [wk(2)] ; xmm1=BE movdqa xmm6,xmm0 punpcklwd xmm0,xmm2 punpckhwd xmm6,xmm2 movdqa xmm5,xmm0 movdqa xmm4,xmm6 pmaddwd xmm0,[GOTOFF(eax,PW_F0299_F0337)] ; xmm0=REL*FIX(0.299)+GEL*FIX(0.337) pmaddwd xmm6,[GOTOFF(eax,PW_F0299_F0337)] ; xmm6=REH*FIX(0.299)+GEH*FIX(0.337) pmaddwd xmm5,[GOTOFF(eax,PW_MF016_MF033)] ; xmm5=REL*-FIX(0.168)+GEL*-FIX(0.331) pmaddwd xmm4,[GOTOFF(eax,PW_MF016_MF033)] ; xmm4=REH*-FIX(0.168)+GEH*-FIX(0.331) movdqa XMMWORD [wk(6)], xmm0 ; wk(6)=REL*FIX(0.299)+GEL*FIX(0.337) movdqa XMMWORD [wk(7)], xmm6 ; wk(7)=REH*FIX(0.299)+GEH*FIX(0.337) pxor xmm0,xmm0 pxor xmm6,xmm6 punpcklwd xmm0,xmm1 ; xmm0=BEL punpckhwd xmm6,xmm1 ; xmm6=BEH psrld xmm0,1 ; xmm0=BEL*FIX(0.500) psrld xmm6,1 ; xmm6=BEH*FIX(0.500) movdqa xmm1,[GOTOFF(eax,PD_ONEHALFM1_CJ)] ; xmm1=[PD_ONEHALFM1_CJ] paddd xmm5,xmm0 paddd xmm4,xmm6 paddd xmm5,xmm1 paddd xmm4,xmm1 psrld xmm5,SCALEBITS ; xmm5=CbEL psrld xmm4,SCALEBITS ; xmm4=CbEH packssdw xmm5,xmm4 ; xmm5=CbE psllw xmm7,BYTE_BIT por xmm5,xmm7 ; xmm5=Cb movdqa XMMWORD [ebx], xmm5 ; Save Cb movdqa xmm0, XMMWORD [wk(3)] ; xmm0=BO movdqa xmm6, XMMWORD [wk(2)] ; xmm6=BE movdqa xmm1, XMMWORD [wk(1)] ; xmm1=RO movdqa xmm4,xmm0 punpcklwd xmm0,xmm3 punpckhwd xmm4,xmm3 movdqa xmm7,xmm0 movdqa xmm5,xmm4 pmaddwd xmm0,[GOTOFF(eax,PW_F0114_F0250)] ; xmm0=BOL*FIX(0.114)+GOL*FIX(0.250) pmaddwd xmm4,[GOTOFF(eax,PW_F0114_F0250)] ; xmm4=BOH*FIX(0.114)+GOH*FIX(0.250) pmaddwd xmm7,[GOTOFF(eax,PW_MF008_MF041)] ; xmm7=BOL*-FIX(0.081)+GOL*-FIX(0.418) pmaddwd xmm5,[GOTOFF(eax,PW_MF008_MF041)] ; xmm5=BOH*-FIX(0.081)+GOH*-FIX(0.418) movdqa xmm3,[GOTOFF(eax,PD_ONEHALF)] ; xmm3=[PD_ONEHALF] paddd xmm0, XMMWORD [wk(4)] paddd xmm4, XMMWORD [wk(5)] paddd xmm0,xmm3 paddd xmm4,xmm3 psrld xmm0,SCALEBITS ; xmm0=YOL psrld xmm4,SCALEBITS ; xmm4=YOH packssdw xmm0,xmm4 ; xmm0=YO pxor xmm3,xmm3 pxor xmm4,xmm4 punpcklwd xmm3,xmm1 ; xmm3=ROL punpckhwd xmm4,xmm1 ; xmm4=ROH psrld xmm3,1 ; xmm3=ROL*FIX(0.500) psrld xmm4,1 ; xmm4=ROH*FIX(0.500) movdqa xmm1,[GOTOFF(eax,PD_ONEHALFM1_CJ)] ; xmm1=[PD_ONEHALFM1_CJ] paddd xmm7,xmm3 paddd xmm5,xmm4 paddd xmm7,xmm1 paddd xmm5,xmm1 psrld xmm7,SCALEBITS ; xmm7=CrOL psrld xmm5,SCALEBITS ; xmm5=CrOH packssdw xmm7,xmm5 ; xmm7=CrO movdqa xmm3, XMMWORD [wk(0)] ; xmm3=RE movdqa xmm4,xmm6 punpcklwd xmm6,xmm2 punpckhwd xmm4,xmm2 movdqa xmm1,xmm6 movdqa xmm5,xmm4 pmaddwd xmm6,[GOTOFF(eax,PW_F0114_F0250)] ; xmm6=BEL*FIX(0.114)+GEL*FIX(0.250) pmaddwd xmm4,[GOTOFF(eax,PW_F0114_F0250)] ; xmm4=BEH*FIX(0.114)+GEH*FIX(0.250) pmaddwd xmm1,[GOTOFF(eax,PW_MF008_MF041)] ; xmm1=BEL*-FIX(0.081)+GEL*-FIX(0.418) pmaddwd xmm5,[GOTOFF(eax,PW_MF008_MF041)] ; xmm5=BEH*-FIX(0.081)+GEH*-FIX(0.418) movdqa xmm2,[GOTOFF(eax,PD_ONEHALF)] ; xmm2=[PD_ONEHALF] paddd xmm6, XMMWORD [wk(6)] paddd xmm4, XMMWORD [wk(7)] paddd xmm6,xmm2 paddd xmm4,xmm2 psrld xmm6,SCALEBITS ; xmm6=YEL psrld xmm4,SCALEBITS ; xmm4=YEH packssdw xmm6,xmm4 ; xmm6=YE psllw xmm0,BYTE_BIT por xmm6,xmm0 ; xmm6=Y movdqa XMMWORD [edi], xmm6 ; Save Y pxor xmm2,xmm2 pxor xmm4,xmm4 punpcklwd xmm2,xmm3 ; xmm2=REL punpckhwd xmm4,xmm3 ; xmm4=REH psrld xmm2,1 ; xmm2=REL*FIX(0.500) psrld xmm4,1 ; xmm4=REH*FIX(0.500) movdqa xmm0,[GOTOFF(eax,PD_ONEHALFM1_CJ)] ; xmm0=[PD_ONEHALFM1_CJ] paddd xmm1,xmm2 paddd xmm5,xmm4 paddd xmm1,xmm0 paddd xmm5,xmm0 psrld xmm1,SCALEBITS ; xmm1=CrEL psrld xmm5,SCALEBITS ; xmm5=CrEH packssdw xmm1,xmm5 ; xmm1=CrE psllw xmm7,BYTE_BIT por xmm1,xmm7 ; xmm1=Cr movdqa XMMWORD [edx], xmm1 ; Save Cr sub ecx, byte SIZEOF_XMMWORD add esi, byte RGB_PIXELSIZE*SIZEOF_XMMWORD ; inptr add edi, byte SIZEOF_XMMWORD ; outptr0 add ebx, byte SIZEOF_XMMWORD ; outptr1 add edx, byte SIZEOF_XMMWORD ; outptr2 cmp ecx, byte SIZEOF_XMMWORD jae near .columnloop test ecx,ecx jnz near .column_ld1 pop ecx ; col pop esi pop edi pop ebx pop edx poppic eax add esi, byte SIZEOF_JSAMPROW ; input_buf add edi, byte SIZEOF_JSAMPROW add ebx, byte SIZEOF_JSAMPROW add edx, byte SIZEOF_JSAMPROW dec eax ; num_rows jg near .rowloop .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