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mozjpeg/simd/jquant-mmx.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

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;
; jquant.asm - sample data conversion and quantization (MMX)
;
; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
;
; 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 "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 16
global EXTN(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
; "How to optimize for the Pentium family of microprocessors"
; (http://www.agner.org/assem/).
;
; 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 16
global EXTN(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 is an annoyingly crappy instruction set. It 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)]
paddw mm0,mm4 ; reciprocal is always negative (MSB=1),
paddw mm1,mm5 ; so we always need to add the initial value
; (input value is never negative as we
; inverted it at the start of this routine)
; 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 16
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