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kc3-lang/libjpeg-turbo/simd/i386/jdcolext-sse2.asm
DRC
- simd/i386/jdcolext-sse2.asm
-
; ; Colorspace conversion (32-bit SSE2) ; ; Copyright 2009, 2012 Pierre Ossman <ossman@cendio.se> for Cendio AB ; Copyright (C) 2012, 2016, 2024-2025, 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) or Yasm. %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 32 GLOBAL_FUNCTION(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 ; --------------- ; NOTE: The values of RGB_RED, RGB_GREEN, and RGB_BLUE determine the ; mapping of components A, B, and C to red, green, and blue. ; ; xmmA = (A0 A2 A4 A6 A8 Aa Ac Ae) = AE ; xmmB = (A1 A3 A5 A7 A9 Ab Ad Af) = AO ; xmmC = (B0 B2 B4 B6 B8 Ba Bc Be) = BE ; xmmD = (B1 B3 B5 B7 B9 Bb Bd Bf) = BO ; xmmE = (C0 C2 C4 C6 C8 Ca Cc Ce) = CE ; xmmF = (C1 C3 C5 C7 C9 Cb Cd Cf) = CO ; xmmG = (** ** ** ** ** ** ** **) ; xmmH = (** ** ** ** ** ** ** **) punpcklbw xmmA, xmmC ; xmmA = (A0 B0 A2 B2 A4 B4 A6 B6 A8 B8 Aa Ba Ac Bc Ae Be) punpcklbw xmmE, xmmB ; xmmE = (C0 A1 C2 A3 C4 A5 C6 A7 C8 A9 Ca Ab Cc Ad Ce Af) punpcklbw xmmD, xmmF ; xmmD = (B1 C1 B3 C3 B5 C5 B7 C7 B9 C9 Bb Cb Bd Cd Bf Cf) movdqa xmmG, xmmA movdqa xmmH, xmmA punpcklwd xmmA, xmmE ; xmmA = (A0 B0 C0 A1 A2 B2 C2 A3 A4 B4 C4 A5 A6 B6 C6 A7) punpckhwd xmmG, xmmE ; xmmG = (A8 B8 C8 A9 Aa Ba Ca Ab Ac Bc Cc Ad Ae Be Ce Af) psrldq xmmH, 2 ; xmmH = (A2 B2 A4 B4 A6 B6 A8 B8 Aa Ba Ac Bc Ae Be -- --) psrldq xmmE, 2 ; xmmE = (C2 A3 C4 A5 C6 A7 C8 A9 Ca Ab Cc Ad Ce Af -- --) movdqa xmmC, xmmD movdqa xmmB, xmmD punpcklwd xmmD, xmmH ; xmmD = (B1 C1 A2 B2 B3 C3 A4 B4 B5 C5 A6 B6 B7 C7 A8 B8) punpckhwd xmmC, xmmH ; xmmC = (B9 C9 Aa Ba Bb Cb Ac Bc Bd Cd Ae Be Bf Cf -- --) psrldq xmmB, 2 ; xmmB = (B3 C3 B5 C5 B7 C7 B9 C9 Bb Cb Bd Cd Bf Cf -- --) movdqa xmmF, xmmE punpcklwd xmmE, xmmB ; xmmE = (C2 A3 B3 C3 C4 A5 B5 C5 C6 A7 B7 C7 C8 A9 B9 C9) punpckhwd xmmF, xmmB ; xmmF = (Ca Ab Bb Cb Cc Ad Bd Cd Ce Af Bf Cf -- -- -- --) pshufd xmmH, xmmA, 0x4E ; xmmH = (A4 B4 C4 A5 A6 B6 C6 A7 A0 B0 C0 A1 A2 B2 C2 A3) movdqa xmmB, xmmE punpckldq xmmA, xmmD ; xmmA = (A0 B0 C0 A1 B1 C1 A2 B2 A2 B2 C2 A3 B3 C3 A4 B4) punpckldq xmmE, xmmH ; xmmE = (C2 A3 B3 C3 A4 B4 C4 A5 C4 A5 B5 C5 A6 B6 C6 A7) punpckhdq xmmD, xmmB ; xmmD = (B5 C5 A6 B6 C6 A7 B7 C7 B7 C7 A8 B8 C8 A9 B9 C9) pshufd xmmH, xmmG, 0x4E ; xmmH = (Ac Bc Cc Ad Ae Be Ce Af A8 B8 C8 A9 Aa Ba Ca Ab) movdqa xmmB, xmmF punpckldq xmmG, xmmC ; xmmG = (A8 B8 C8 A9 B9 C9 Aa Ba Aa Ba Ca Ab Bb Cb Ac Bc) punpckldq xmmF, xmmH ; xmmF = (Ca Ab Bb Cb Ac Bc Cc Ad Cc Ad Bd Cd Ae Be Ce Af) punpckhdq xmmC, xmmB ; xmmC = (Bd Cd Ae Be Ce Af Bf Cf Bf Cf -- -- -- -- -- --) punpcklqdq xmmA, xmmE ; xmmA = (A0 B0 C0 A1 B1 C1 A2 B2 C2 A3 B3 C3 A4 B4 C4 A5) punpcklqdq xmmD, xmmG ; xmmD = (B5 C5 A6 B6 C6 A7 B7 C7 A8 B8 C8 A9 B9 C9 Aa Ba) punpcklqdq xmmF, xmmC ; xmmF = (Ca Ab Bb Cb Ac Bc Cc Ad Bd Cd Ae Be Ce Af Bf Cf) 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 ; NOTE: The values of RGB_RED, RGB_GREEN, and RGB_BLUE determine the ; mapping of components A, B, C, and D to red, green, and blue. ; ; xmmA = (A0 A2 A4 A6 A8 Aa Ac Ae) = AE ; xmmB = (A1 A3 A5 A7 A9 Ab Ad Af) = AO ; xmmC = (B0 B2 B4 B6 B8 Ba Bc Be) = BE ; xmmD = (B1 B3 B5 B7 B9 Bb Bd Bf) = BO ; xmmE = (C0 C2 C4 C6 C8 Ca Cc Ce) = CE ; xmmF = (C1 C3 C5 C7 C9 Cb Cd Cf) = CO ; xmmG = (D0 D2 D4 D6 D8 Da Dc De) = DE ; xmmH = (D1 D3 D5 D7 D9 Db Dd Df) = DO punpcklbw xmmA, xmmC ; xmmA = (A0 B0 A2 B2 A4 B4 A6 B6 A8 B8 Aa Ba Ac Bc Ae Be) punpcklbw xmmE, xmmG ; xmmE = (C0 D0 C2 D2 C4 D4 C6 D6 C8 D8 Ca Da Cc Dc Ce De) punpcklbw xmmB, xmmD ; xmmB = (A1 B1 A3 B3 A5 B5 A7 B7 A9 B9 Ab Bb Ad Bd Af Bf) punpcklbw xmmF, xmmH ; xmmF = (C1 D1 C3 D3 C5 D5 C7 D7 C9 D9 Cb Db Cd Dd Cf Df) movdqa xmmC, xmmA punpcklwd xmmA, xmmE ; xmmA = (A0 B0 C0 D0 A2 B2 C2 D2 A4 B4 C4 D4 A6 B6 C6 D6) punpckhwd xmmC, xmmE ; xmmC = (A8 B8 C8 D8 Aa Ba Ca Da Ac Bc Cc Dc Ae Be Ce De) movdqa xmmG, xmmB punpcklwd xmmB, xmmF ; xmmB = (A1 B1 C1 D1 A3 B3 C3 D3 A5 B5 C5 D5 A7 B7 C7 D7) punpckhwd xmmG, xmmF ; xmmG = (A9 B9 C9 D9 Ab Bb Cb Db Ad Bd Cd Dd Af Bf Cf Df) movdqa xmmD, xmmA punpckldq xmmA, xmmB ; xmmA = (A0 B0 C0 D0 A1 B1 C1 D1 A2 B2 C2 D2 A3 B3 C3 D3) punpckhdq xmmD, xmmB ; xmmD = (A4 B4 C4 D4 A5 B5 C5 D5 A6 B6 C6 D6 A7 B7 C7 D7) movdqa xmmH, xmmC punpckldq xmmC, xmmG ; xmmC = (A8 B8 C8 D8 A9 B9 C9 D9 Aa Ba Ca Da Ab Bb Cb Db) punpckhdq xmmH, xmmG ; xmmH = (Ac Bc Cc Dc Ad Bd Cd Dd Ae Be Ce De Af Bf Cf Df) 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 32