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kc3-lang/libjpeg-turbo/simd/i386/jquant-mmx.asm
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- simd/i386/jquant-mmx.asm
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; ; Sample data conversion and quantization (32-bit MMX) ; ; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB ; Copyright (C) 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 "jsimdext.inc" %include "jdct.inc" ; -------------------------------------------------------------------------- SECTION SEG_TEXT BITS 32 ; Load data into workspace, applying unsigned->signed conversion ; ; GLOBAL(void) ; jsimd_convsamp_mmx(JSAMPARRAY sample_data, JDIMENSION start_col, ; DCTELEM *workspace) %define sample_data ebp + 8 ; JSAMPARRAY sample_data %define start_col ebp + 12 ; JDIMENSION start_col %define workspace ebp + 16 ; DCTELEM *workspace align 32 GLOBAL_FUNCTION(jsimd_convsamp_mmx) EXTN(jsimd_convsamp_mmx): push ebp mov ebp, esp push ebx ; push ecx ; need not be preserved ; push edx ; need not be preserved push esi push edi pxor mm6, mm6 ; mm6 = (all 0's) pcmpeqw mm7, mm7 psllw mm7, 7 ; mm7 = { 0xFF80 0xFF80 0xFF80 0xFF80 } mov esi, JSAMPARRAY [sample_data] ; (JSAMPROW *) mov eax, JDIMENSION [start_col] mov edi, POINTER [workspace] ; (DCTELEM *) mov ecx, DCTSIZE / 4 ALIGNX 16, 7 .convloop: mov ebx, JSAMPROW [esi + 0 * SIZEOF_JSAMPROW] ; (JSAMPLE *) mov edx, JSAMPROW [esi + 1 * SIZEOF_JSAMPROW] ; (JSAMPLE *) movq mm0, MMWORD [ebx + eax * SIZEOF_JSAMPLE] ; mm0 = (01234567) movq mm1, MMWORD [edx + eax * SIZEOF_JSAMPLE] ; mm1 = (89abcdef) mov ebx, JSAMPROW [esi + 2 * SIZEOF_JSAMPROW] ; (JSAMPLE *) mov edx, JSAMPROW [esi + 3 * SIZEOF_JSAMPROW] ; (JSAMPLE *) movq mm2, MMWORD [ebx + eax * SIZEOF_JSAMPLE] ; mm2 = (ghijklmn) movq mm3, MMWORD [edx + eax * SIZEOF_JSAMPLE] ; mm3 = (opqrstuv) movq mm4, mm0 punpcklbw mm0, mm6 ; mm0 = (0123) punpckhbw mm4, mm6 ; mm4 = (4567) movq mm5, mm1 punpcklbw mm1, mm6 ; mm1 = (89ab) punpckhbw mm5, mm6 ; mm5 = (cdef) paddw mm0, mm7 paddw mm4, mm7 paddw mm1, mm7 paddw mm5, mm7 movq MMWORD [MMBLOCK(0, 0, edi, SIZEOF_DCTELEM)], mm0 movq MMWORD [MMBLOCK(0, 1, edi, SIZEOF_DCTELEM)], mm4 movq MMWORD [MMBLOCK(1, 0, edi, SIZEOF_DCTELEM)], mm1 movq MMWORD [MMBLOCK(1, 1, edi, SIZEOF_DCTELEM)], mm5 movq mm0, mm2 punpcklbw mm2, mm6 ; mm2 = (ghij) punpckhbw mm0, mm6 ; mm0 = (klmn) movq mm4, mm3 punpcklbw mm3, mm6 ; mm3 = (opqr) punpckhbw mm4, mm6 ; mm4 = (stuv) paddw mm2, mm7 paddw mm0, mm7 paddw mm3, mm7 paddw mm4, mm7 movq MMWORD [MMBLOCK(2, 0, edi, SIZEOF_DCTELEM)], mm2 movq MMWORD [MMBLOCK(2, 1, edi, SIZEOF_DCTELEM)], mm0 movq MMWORD [MMBLOCK(3, 0, edi, SIZEOF_DCTELEM)], mm3 movq MMWORD [MMBLOCK(3, 1, edi, SIZEOF_DCTELEM)], mm4 add esi, byte 4 * SIZEOF_JSAMPROW add edi, byte 4 * DCTSIZE * SIZEOF_DCTELEM dec ecx jnz short .convloop emms ; empty MMX state pop edi pop esi ; pop edx ; need not be preserved ; pop ecx ; need not be preserved pop ebx pop ebp ret ; -------------------------------------------------------------------------- ; ; Quantize/descale the coefficients, and store into coef_block ; ; This implementation is based on an algorithm described in ; "Optimizing subroutines in assembly language: ; An optimization guide for x86 platforms" (https://agner.org/optimize). ; ; GLOBAL(void) ; jsimd_quantize_mmx(JCOEFPTR coef_block, DCTELEM *divisors, ; DCTELEM *workspace) %define RECIPROCAL(m, n, b) \ MMBLOCK(DCTSIZE * 0 + (m), (n), (b), SIZEOF_DCTELEM) %define CORRECTION(m, n, b) \ MMBLOCK(DCTSIZE * 1 + (m), (n), (b), SIZEOF_DCTELEM) %define SCALE(m, n, b) \ MMBLOCK(DCTSIZE * 2 + (m), (n), (b), SIZEOF_DCTELEM) %define SHIFT(m, n, b) \ MMBLOCK(DCTSIZE * 3 + (m), (n), (b), SIZEOF_DCTELEM) %define coef_block ebp + 8 ; JCOEFPTR coef_block %define divisors ebp + 12 ; DCTELEM *divisors %define workspace ebp + 16 ; DCTELEM *workspace align 32 GLOBAL_FUNCTION(jsimd_quantize_mmx) EXTN(jsimd_quantize_mmx): push ebp mov ebp, esp ; push ebx ; unused ; push ecx ; unused ; push edx ; need not be preserved push esi push edi mov esi, POINTER [workspace] mov edx, POINTER [divisors] mov edi, JCOEFPTR [coef_block] mov ah, 2 ALIGNX 16, 7 .quantloop1: mov al, DCTSIZE2 / 8 / 2 ALIGNX 16, 7 .quantloop2: movq mm2, MMWORD [MMBLOCK(0, 0, esi, SIZEOF_DCTELEM)] movq mm3, MMWORD [MMBLOCK(0, 1, esi, SIZEOF_DCTELEM)] movq mm0, mm2 movq mm1, mm3 psraw mm2, (WORD_BIT - 1) ; -1 if value < 0, 0 otherwise psraw mm3, (WORD_BIT - 1) pxor mm0, mm2 ; val = -val pxor mm1, mm3 psubw mm0, mm2 psubw mm1, mm3 ; MMX has two misfeatures that are causing problems here: ; ; - All multiplications are signed. ; - The second operand for the shifts is not treated as packed. ; ; We work around the first problem by implementing this algorithm: ; ; unsigned long unsigned_multiply(unsigned short x, unsigned short y) ; { ; enum { SHORT_BIT = 16 }; ; signed short sx = (signed short)x; ; signed short sy = (signed short)y; ; signed long sz; ; ; sz = (long)sx * (long)sy; /* signed multiply */ ; ; if (sx < 0) sz += (long)sy << SHORT_BIT; ; if (sy < 0) sz += (long)sx << SHORT_BIT; ; ; return (unsigned long)sz; ; } ; ; (note that a negative sx adds _sy_ and vice versa) ; ; For the second problem, we replace the shift by a multiplication. ; Unfortunately that means we have to deal with the signed issue again. paddw mm0, MMWORD [CORRECTION(0, 0, edx)] ; correction + roundfactor paddw mm1, MMWORD [CORRECTION(0, 1, edx)] movq mm4, mm0 ; store current value for later movq mm5, mm1 pmulhw mm0, MMWORD [RECIPROCAL(0, 0, edx)] ; reciprocal pmulhw mm1, MMWORD [RECIPROCAL(0, 1, edx)] ; reciprocal is always negative (MSB = 1), so we always need to add the ; initial value. (The input value is never negative, as we inverted it at ; the start of this routine.) paddw mm0, mm4 paddw mm1, mm5 ; Here it gets a bit tricky, as both scale and mm0/mm1 can be negative. movq mm6, MMWORD [SCALE(0, 0, edx)] ; scale movq mm7, MMWORD [SCALE(0, 1, edx)] movq mm4, mm0 movq mm5, mm1 pmulhw mm0, mm6 pmulhw mm1, mm7 psraw mm6, (WORD_BIT - 1) ; determine if scale is negative psraw mm7, (WORD_BIT - 1) pand mm6, mm4 ; and add input if it is pand mm7, mm5 paddw mm0, mm6 paddw mm1, mm7 psraw mm4, (WORD_BIT - 1) ; then check if negative input psraw mm5, (WORD_BIT - 1) pand mm4, MMWORD [SCALE(0, 0, edx)] ; and add scale if it is pand mm5, MMWORD [SCALE(0, 1, edx)] paddw mm0, mm4 paddw mm1, mm5 pxor mm0, mm2 ; val = -val pxor mm1, mm3 psubw mm0, mm2 psubw mm1, mm3 movq MMWORD [MMBLOCK(0, 0, edi, SIZEOF_DCTELEM)], mm0 movq MMWORD [MMBLOCK(0, 1, edi, SIZEOF_DCTELEM)], mm1 add esi, byte 8 * SIZEOF_DCTELEM add edx, byte 8 * SIZEOF_DCTELEM add edi, byte 8 * SIZEOF_JCOEF dec al jnz near .quantloop2 dec ah jnz near .quantloop1 ; to avoid branch misprediction emms ; empty MMX state pop edi pop esi ; pop edx ; need not be preserved ; pop ecx ; unused ; pop ebx ; unused 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