Files
mozjpeg/simd/jidctint-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

859 lines
35 KiB
NASM

;
; jidctint.asm - accurate integer IDCT (SSE2)
;
; 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
;
; This file contains a slow-but-accurate integer implementation of the
; inverse DCT (Discrete Cosine Transform). The following code is based
; directly on the IJG's original jidctint.c; see the jidctint.c for
; more details.
;
; [TAB8]
%include "jsimdext.inc"
%include "jdct.inc"
; --------------------------------------------------------------------------
%define CONST_BITS 13
%define PASS1_BITS 2
%define DESCALE_P1 (CONST_BITS-PASS1_BITS)
%define DESCALE_P2 (CONST_BITS+PASS1_BITS+3)
%if CONST_BITS == 13
F_0_298 equ 2446 ; FIX(0.298631336)
F_0_390 equ 3196 ; FIX(0.390180644)
F_0_541 equ 4433 ; FIX(0.541196100)
F_0_765 equ 6270 ; FIX(0.765366865)
F_0_899 equ 7373 ; FIX(0.899976223)
F_1_175 equ 9633 ; FIX(1.175875602)
F_1_501 equ 12299 ; FIX(1.501321110)
F_1_847 equ 15137 ; FIX(1.847759065)
F_1_961 equ 16069 ; FIX(1.961570560)
F_2_053 equ 16819 ; FIX(2.053119869)
F_2_562 equ 20995 ; FIX(2.562915447)
F_3_072 equ 25172 ; FIX(3.072711026)
%else
; NASM cannot do compile-time arithmetic on floating-point constants.
%define DESCALE(x,n) (((x)+(1<<((n)-1)))>>(n))
F_0_298 equ DESCALE( 320652955,30-CONST_BITS) ; FIX(0.298631336)
F_0_390 equ DESCALE( 418953276,30-CONST_BITS) ; FIX(0.390180644)
F_0_541 equ DESCALE( 581104887,30-CONST_BITS) ; FIX(0.541196100)
F_0_765 equ DESCALE( 821806413,30-CONST_BITS) ; FIX(0.765366865)
F_0_899 equ DESCALE( 966342111,30-CONST_BITS) ; FIX(0.899976223)
F_1_175 equ DESCALE(1262586813,30-CONST_BITS) ; FIX(1.175875602)
F_1_501 equ DESCALE(1612031267,30-CONST_BITS) ; FIX(1.501321110)
F_1_847 equ DESCALE(1984016188,30-CONST_BITS) ; FIX(1.847759065)
F_1_961 equ DESCALE(2106220350,30-CONST_BITS) ; FIX(1.961570560)
F_2_053 equ DESCALE(2204520673,30-CONST_BITS) ; FIX(2.053119869)
F_2_562 equ DESCALE(2751909506,30-CONST_BITS) ; FIX(2.562915447)
F_3_072 equ DESCALE(3299298341,30-CONST_BITS) ; FIX(3.072711026)
%endif
; --------------------------------------------------------------------------
SECTION SEG_CONST
alignz 16
global EXTN(jconst_idct_islow_sse2)
EXTN(jconst_idct_islow_sse2):
PW_F130_F054 times 4 dw (F_0_541+F_0_765), F_0_541
PW_F054_MF130 times 4 dw F_0_541, (F_0_541-F_1_847)
PW_MF078_F117 times 4 dw (F_1_175-F_1_961), F_1_175
PW_F117_F078 times 4 dw F_1_175, (F_1_175-F_0_390)
PW_MF060_MF089 times 4 dw (F_0_298-F_0_899),-F_0_899
PW_MF089_F060 times 4 dw -F_0_899, (F_1_501-F_0_899)
PW_MF050_MF256 times 4 dw (F_2_053-F_2_562),-F_2_562
PW_MF256_F050 times 4 dw -F_2_562, (F_3_072-F_2_562)
PD_DESCALE_P1 times 4 dd 1 << (DESCALE_P1-1)
PD_DESCALE_P2 times 4 dd 1 << (DESCALE_P2-1)
PB_CENTERJSAMP times 16 db CENTERJSAMPLE
alignz 16
; --------------------------------------------------------------------------
SECTION SEG_TEXT
BITS 32
;
; Perform dequantization and inverse DCT on one block of coefficients.
;
; GLOBAL(void)
; jsimd_idct_islow_sse2 (void *dct_table, JCOEFPTR coef_block,
; JSAMPARRAY output_buf, JDIMENSION output_col)
;
%define dct_table(b) (b)+8 ; jpeg_component_info *compptr
%define coef_block(b) (b)+12 ; JCOEFPTR coef_block
%define output_buf(b) (b)+16 ; JSAMPARRAY output_buf
%define output_col(b) (b)+20 ; JDIMENSION output_col
%define original_ebp ebp+0
%define wk(i) ebp-(WK_NUM-(i))*SIZEOF_XMMWORD ; xmmword wk[WK_NUM]
%define WK_NUM 12
align 16
global EXTN(jsimd_idct_islow_sse2)
EXTN(jsimd_idct_islow_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 ebx
; push ecx ; unused
; push edx ; need not be preserved
push esi
push edi
get_GOT ebx ; get GOT address
; ---- Pass 1: process columns from input.
; mov eax, [original_ebp]
mov edx, POINTER [dct_table(eax)] ; quantptr
mov esi, JCOEFPTR [coef_block(eax)] ; inptr
%ifndef NO_ZERO_COLUMN_TEST_ISLOW_SSE2
mov eax, DWORD [DWBLOCK(1,0,esi,SIZEOF_JCOEF)]
or eax, DWORD [DWBLOCK(2,0,esi,SIZEOF_JCOEF)]
jnz near .columnDCT
movdqa xmm0, XMMWORD [XMMBLOCK(1,0,esi,SIZEOF_JCOEF)]
movdqa xmm1, XMMWORD [XMMBLOCK(2,0,esi,SIZEOF_JCOEF)]
por xmm0, XMMWORD [XMMBLOCK(3,0,esi,SIZEOF_JCOEF)]
por xmm1, XMMWORD [XMMBLOCK(4,0,esi,SIZEOF_JCOEF)]
por xmm0, XMMWORD [XMMBLOCK(5,0,esi,SIZEOF_JCOEF)]
por xmm1, XMMWORD [XMMBLOCK(6,0,esi,SIZEOF_JCOEF)]
por xmm0, XMMWORD [XMMBLOCK(7,0,esi,SIZEOF_JCOEF)]
por xmm1,xmm0
packsswb xmm1,xmm1
packsswb xmm1,xmm1
movd eax,xmm1
test eax,eax
jnz short .columnDCT
; -- AC terms all zero
movdqa xmm5, XMMWORD [XMMBLOCK(0,0,esi,SIZEOF_JCOEF)]
pmullw xmm5, XMMWORD [XMMBLOCK(0,0,edx,SIZEOF_ISLOW_MULT_TYPE)]
psllw xmm5,PASS1_BITS
movdqa xmm4,xmm5 ; xmm5=in0=(00 01 02 03 04 05 06 07)
punpcklwd xmm5,xmm5 ; xmm5=(00 00 01 01 02 02 03 03)
punpckhwd xmm4,xmm4 ; xmm4=(04 04 05 05 06 06 07 07)
pshufd xmm7,xmm5,0x00 ; xmm7=col0=(00 00 00 00 00 00 00 00)
pshufd xmm6,xmm5,0x55 ; xmm6=col1=(01 01 01 01 01 01 01 01)
pshufd xmm1,xmm5,0xAA ; xmm1=col2=(02 02 02 02 02 02 02 02)
pshufd xmm5,xmm5,0xFF ; xmm5=col3=(03 03 03 03 03 03 03 03)
pshufd xmm0,xmm4,0x00 ; xmm0=col4=(04 04 04 04 04 04 04 04)
pshufd xmm3,xmm4,0x55 ; xmm3=col5=(05 05 05 05 05 05 05 05)
pshufd xmm2,xmm4,0xAA ; xmm2=col6=(06 06 06 06 06 06 06 06)
pshufd xmm4,xmm4,0xFF ; xmm4=col7=(07 07 07 07 07 07 07 07)
movdqa XMMWORD [wk(8)], xmm6 ; wk(8)=col1
movdqa XMMWORD [wk(9)], xmm5 ; wk(9)=col3
movdqa XMMWORD [wk(10)], xmm3 ; wk(10)=col5
movdqa XMMWORD [wk(11)], xmm4 ; wk(11)=col7
jmp near .column_end
alignx 16,7
%endif
.columnDCT:
; -- Even part
movdqa xmm0, XMMWORD [XMMBLOCK(0,0,esi,SIZEOF_JCOEF)]
movdqa xmm1, XMMWORD [XMMBLOCK(2,0,esi,SIZEOF_JCOEF)]
pmullw xmm0, XMMWORD [XMMBLOCK(0,0,edx,SIZEOF_ISLOW_MULT_TYPE)]
pmullw xmm1, XMMWORD [XMMBLOCK(2,0,edx,SIZEOF_ISLOW_MULT_TYPE)]
movdqa xmm2, XMMWORD [XMMBLOCK(4,0,esi,SIZEOF_JCOEF)]
movdqa xmm3, XMMWORD [XMMBLOCK(6,0,esi,SIZEOF_JCOEF)]
pmullw xmm2, XMMWORD [XMMBLOCK(4,0,edx,SIZEOF_ISLOW_MULT_TYPE)]
pmullw xmm3, XMMWORD [XMMBLOCK(6,0,edx,SIZEOF_ISLOW_MULT_TYPE)]
; (Original)
; z1 = (z2 + z3) * 0.541196100;
; tmp2 = z1 + z3 * -1.847759065;
; tmp3 = z1 + z2 * 0.765366865;
;
; (This implementation)
; tmp2 = z2 * 0.541196100 + z3 * (0.541196100 - 1.847759065);
; tmp3 = z2 * (0.541196100 + 0.765366865) + z3 * 0.541196100;
movdqa xmm4,xmm1 ; xmm1=in2=z2
movdqa xmm5,xmm1
punpcklwd xmm4,xmm3 ; xmm3=in6=z3
punpckhwd xmm5,xmm3
movdqa xmm1,xmm4
movdqa xmm3,xmm5
pmaddwd xmm4,[GOTOFF(ebx,PW_F130_F054)] ; xmm4=tmp3L
pmaddwd xmm5,[GOTOFF(ebx,PW_F130_F054)] ; xmm5=tmp3H
pmaddwd xmm1,[GOTOFF(ebx,PW_F054_MF130)] ; xmm1=tmp2L
pmaddwd xmm3,[GOTOFF(ebx,PW_F054_MF130)] ; xmm3=tmp2H
movdqa xmm6,xmm0
paddw xmm0,xmm2 ; xmm0=in0+in4
psubw xmm6,xmm2 ; xmm6=in0-in4
pxor xmm7,xmm7
pxor xmm2,xmm2
punpcklwd xmm7,xmm0 ; xmm7=tmp0L
punpckhwd xmm2,xmm0 ; xmm2=tmp0H
psrad xmm7,(16-CONST_BITS) ; psrad xmm7,16 & pslld xmm7,CONST_BITS
psrad xmm2,(16-CONST_BITS) ; psrad xmm2,16 & pslld xmm2,CONST_BITS
movdqa xmm0,xmm7
paddd xmm7,xmm4 ; xmm7=tmp10L
psubd xmm0,xmm4 ; xmm0=tmp13L
movdqa xmm4,xmm2
paddd xmm2,xmm5 ; xmm2=tmp10H
psubd xmm4,xmm5 ; xmm4=tmp13H
movdqa XMMWORD [wk(0)], xmm7 ; wk(0)=tmp10L
movdqa XMMWORD [wk(1)], xmm2 ; wk(1)=tmp10H
movdqa XMMWORD [wk(2)], xmm0 ; wk(2)=tmp13L
movdqa XMMWORD [wk(3)], xmm4 ; wk(3)=tmp13H
pxor xmm5,xmm5
pxor xmm7,xmm7
punpcklwd xmm5,xmm6 ; xmm5=tmp1L
punpckhwd xmm7,xmm6 ; xmm7=tmp1H
psrad xmm5,(16-CONST_BITS) ; psrad xmm5,16 & pslld xmm5,CONST_BITS
psrad xmm7,(16-CONST_BITS) ; psrad xmm7,16 & pslld xmm7,CONST_BITS
movdqa xmm2,xmm5
paddd xmm5,xmm1 ; xmm5=tmp11L
psubd xmm2,xmm1 ; xmm2=tmp12L
movdqa xmm0,xmm7
paddd xmm7,xmm3 ; xmm7=tmp11H
psubd xmm0,xmm3 ; xmm0=tmp12H
movdqa XMMWORD [wk(4)], xmm5 ; wk(4)=tmp11L
movdqa XMMWORD [wk(5)], xmm7 ; wk(5)=tmp11H
movdqa XMMWORD [wk(6)], xmm2 ; wk(6)=tmp12L
movdqa XMMWORD [wk(7)], xmm0 ; wk(7)=tmp12H
; -- Odd part
movdqa xmm4, XMMWORD [XMMBLOCK(1,0,esi,SIZEOF_JCOEF)]
movdqa xmm6, XMMWORD [XMMBLOCK(3,0,esi,SIZEOF_JCOEF)]
pmullw xmm4, XMMWORD [XMMBLOCK(1,0,edx,SIZEOF_ISLOW_MULT_TYPE)]
pmullw xmm6, XMMWORD [XMMBLOCK(3,0,edx,SIZEOF_ISLOW_MULT_TYPE)]
movdqa xmm1, XMMWORD [XMMBLOCK(5,0,esi,SIZEOF_JCOEF)]
movdqa xmm3, XMMWORD [XMMBLOCK(7,0,esi,SIZEOF_JCOEF)]
pmullw xmm1, XMMWORD [XMMBLOCK(5,0,edx,SIZEOF_ISLOW_MULT_TYPE)]
pmullw xmm3, XMMWORD [XMMBLOCK(7,0,edx,SIZEOF_ISLOW_MULT_TYPE)]
movdqa xmm5,xmm6
movdqa xmm7,xmm4
paddw xmm5,xmm3 ; xmm5=z3
paddw xmm7,xmm1 ; xmm7=z4
; (Original)
; z5 = (z3 + z4) * 1.175875602;
; z3 = z3 * -1.961570560; z4 = z4 * -0.390180644;
; z3 += z5; z4 += z5;
;
; (This implementation)
; z3 = z3 * (1.175875602 - 1.961570560) + z4 * 1.175875602;
; z4 = z3 * 1.175875602 + z4 * (1.175875602 - 0.390180644);
movdqa xmm2,xmm5
movdqa xmm0,xmm5
punpcklwd xmm2,xmm7
punpckhwd xmm0,xmm7
movdqa xmm5,xmm2
movdqa xmm7,xmm0
pmaddwd xmm2,[GOTOFF(ebx,PW_MF078_F117)] ; xmm2=z3L
pmaddwd xmm0,[GOTOFF(ebx,PW_MF078_F117)] ; xmm0=z3H
pmaddwd xmm5,[GOTOFF(ebx,PW_F117_F078)] ; xmm5=z4L
pmaddwd xmm7,[GOTOFF(ebx,PW_F117_F078)] ; xmm7=z4H
movdqa XMMWORD [wk(10)], xmm2 ; wk(10)=z3L
movdqa XMMWORD [wk(11)], xmm0 ; wk(11)=z3H
; (Original)
; z1 = tmp0 + tmp3; z2 = tmp1 + tmp2;
; tmp0 = tmp0 * 0.298631336; tmp1 = tmp1 * 2.053119869;
; tmp2 = tmp2 * 3.072711026; tmp3 = tmp3 * 1.501321110;
; z1 = z1 * -0.899976223; z2 = z2 * -2.562915447;
; tmp0 += z1 + z3; tmp1 += z2 + z4;
; tmp2 += z2 + z3; tmp3 += z1 + z4;
;
; (This implementation)
; tmp0 = tmp0 * (0.298631336 - 0.899976223) + tmp3 * -0.899976223;
; tmp1 = tmp1 * (2.053119869 - 2.562915447) + tmp2 * -2.562915447;
; tmp2 = tmp1 * -2.562915447 + tmp2 * (3.072711026 - 2.562915447);
; tmp3 = tmp0 * -0.899976223 + tmp3 * (1.501321110 - 0.899976223);
; tmp0 += z3; tmp1 += z4;
; tmp2 += z3; tmp3 += z4;
movdqa xmm2,xmm3
movdqa xmm0,xmm3
punpcklwd xmm2,xmm4
punpckhwd xmm0,xmm4
movdqa xmm3,xmm2
movdqa xmm4,xmm0
pmaddwd xmm2,[GOTOFF(ebx,PW_MF060_MF089)] ; xmm2=tmp0L
pmaddwd xmm0,[GOTOFF(ebx,PW_MF060_MF089)] ; xmm0=tmp0H
pmaddwd xmm3,[GOTOFF(ebx,PW_MF089_F060)] ; xmm3=tmp3L
pmaddwd xmm4,[GOTOFF(ebx,PW_MF089_F060)] ; xmm4=tmp3H
paddd xmm2, XMMWORD [wk(10)] ; xmm2=tmp0L
paddd xmm0, XMMWORD [wk(11)] ; xmm0=tmp0H
paddd xmm3,xmm5 ; xmm3=tmp3L
paddd xmm4,xmm7 ; xmm4=tmp3H
movdqa XMMWORD [wk(8)], xmm2 ; wk(8)=tmp0L
movdqa XMMWORD [wk(9)], xmm0 ; wk(9)=tmp0H
movdqa xmm2,xmm1
movdqa xmm0,xmm1
punpcklwd xmm2,xmm6
punpckhwd xmm0,xmm6
movdqa xmm1,xmm2
movdqa xmm6,xmm0
pmaddwd xmm2,[GOTOFF(ebx,PW_MF050_MF256)] ; xmm2=tmp1L
pmaddwd xmm0,[GOTOFF(ebx,PW_MF050_MF256)] ; xmm0=tmp1H
pmaddwd xmm1,[GOTOFF(ebx,PW_MF256_F050)] ; xmm1=tmp2L
pmaddwd xmm6,[GOTOFF(ebx,PW_MF256_F050)] ; xmm6=tmp2H
paddd xmm2,xmm5 ; xmm2=tmp1L
paddd xmm0,xmm7 ; xmm0=tmp1H
paddd xmm1, XMMWORD [wk(10)] ; xmm1=tmp2L
paddd xmm6, XMMWORD [wk(11)] ; xmm6=tmp2H
movdqa XMMWORD [wk(10)], xmm2 ; wk(10)=tmp1L
movdqa XMMWORD [wk(11)], xmm0 ; wk(11)=tmp1H
; -- Final output stage
movdqa xmm5, XMMWORD [wk(0)] ; xmm5=tmp10L
movdqa xmm7, XMMWORD [wk(1)] ; xmm7=tmp10H
movdqa xmm2,xmm5
movdqa xmm0,xmm7
paddd xmm5,xmm3 ; xmm5=data0L
paddd xmm7,xmm4 ; xmm7=data0H
psubd xmm2,xmm3 ; xmm2=data7L
psubd xmm0,xmm4 ; xmm0=data7H
movdqa xmm3,[GOTOFF(ebx,PD_DESCALE_P1)] ; xmm3=[PD_DESCALE_P1]
paddd xmm5,xmm3
paddd xmm7,xmm3
psrad xmm5,DESCALE_P1
psrad xmm7,DESCALE_P1
paddd xmm2,xmm3
paddd xmm0,xmm3
psrad xmm2,DESCALE_P1
psrad xmm0,DESCALE_P1
packssdw xmm5,xmm7 ; xmm5=data0=(00 01 02 03 04 05 06 07)
packssdw xmm2,xmm0 ; xmm2=data7=(70 71 72 73 74 75 76 77)
movdqa xmm4, XMMWORD [wk(4)] ; xmm4=tmp11L
movdqa xmm3, XMMWORD [wk(5)] ; xmm3=tmp11H
movdqa xmm7,xmm4
movdqa xmm0,xmm3
paddd xmm4,xmm1 ; xmm4=data1L
paddd xmm3,xmm6 ; xmm3=data1H
psubd xmm7,xmm1 ; xmm7=data6L
psubd xmm0,xmm6 ; xmm0=data6H
movdqa xmm1,[GOTOFF(ebx,PD_DESCALE_P1)] ; xmm1=[PD_DESCALE_P1]
paddd xmm4,xmm1
paddd xmm3,xmm1
psrad xmm4,DESCALE_P1
psrad xmm3,DESCALE_P1
paddd xmm7,xmm1
paddd xmm0,xmm1
psrad xmm7,DESCALE_P1
psrad xmm0,DESCALE_P1
packssdw xmm4,xmm3 ; xmm4=data1=(10 11 12 13 14 15 16 17)
packssdw xmm7,xmm0 ; xmm7=data6=(60 61 62 63 64 65 66 67)
movdqa xmm6,xmm5 ; transpose coefficients(phase 1)
punpcklwd xmm5,xmm4 ; xmm5=(00 10 01 11 02 12 03 13)
punpckhwd xmm6,xmm4 ; xmm6=(04 14 05 15 06 16 07 17)
movdqa xmm1,xmm7 ; transpose coefficients(phase 1)
punpcklwd xmm7,xmm2 ; xmm7=(60 70 61 71 62 72 63 73)
punpckhwd xmm1,xmm2 ; xmm1=(64 74 65 75 66 76 67 77)
movdqa xmm3, XMMWORD [wk(6)] ; xmm3=tmp12L
movdqa xmm0, XMMWORD [wk(7)] ; xmm0=tmp12H
movdqa xmm4, XMMWORD [wk(10)] ; xmm4=tmp1L
movdqa xmm2, XMMWORD [wk(11)] ; xmm2=tmp1H
movdqa XMMWORD [wk(0)], xmm5 ; wk(0)=(00 10 01 11 02 12 03 13)
movdqa XMMWORD [wk(1)], xmm6 ; wk(1)=(04 14 05 15 06 16 07 17)
movdqa XMMWORD [wk(4)], xmm7 ; wk(4)=(60 70 61 71 62 72 63 73)
movdqa XMMWORD [wk(5)], xmm1 ; wk(5)=(64 74 65 75 66 76 67 77)
movdqa xmm5,xmm3
movdqa xmm6,xmm0
paddd xmm3,xmm4 ; xmm3=data2L
paddd xmm0,xmm2 ; xmm0=data2H
psubd xmm5,xmm4 ; xmm5=data5L
psubd xmm6,xmm2 ; xmm6=data5H
movdqa xmm7,[GOTOFF(ebx,PD_DESCALE_P1)] ; xmm7=[PD_DESCALE_P1]
paddd xmm3,xmm7
paddd xmm0,xmm7
psrad xmm3,DESCALE_P1
psrad xmm0,DESCALE_P1
paddd xmm5,xmm7
paddd xmm6,xmm7
psrad xmm5,DESCALE_P1
psrad xmm6,DESCALE_P1
packssdw xmm3,xmm0 ; xmm3=data2=(20 21 22 23 24 25 26 27)
packssdw xmm5,xmm6 ; xmm5=data5=(50 51 52 53 54 55 56 57)
movdqa xmm1, XMMWORD [wk(2)] ; xmm1=tmp13L
movdqa xmm4, XMMWORD [wk(3)] ; xmm4=tmp13H
movdqa xmm2, XMMWORD [wk(8)] ; xmm2=tmp0L
movdqa xmm7, XMMWORD [wk(9)] ; xmm7=tmp0H
movdqa xmm0,xmm1
movdqa xmm6,xmm4
paddd xmm1,xmm2 ; xmm1=data3L
paddd xmm4,xmm7 ; xmm4=data3H
psubd xmm0,xmm2 ; xmm0=data4L
psubd xmm6,xmm7 ; xmm6=data4H
movdqa xmm2,[GOTOFF(ebx,PD_DESCALE_P1)] ; xmm2=[PD_DESCALE_P1]
paddd xmm1,xmm2
paddd xmm4,xmm2
psrad xmm1,DESCALE_P1
psrad xmm4,DESCALE_P1
paddd xmm0,xmm2
paddd xmm6,xmm2
psrad xmm0,DESCALE_P1
psrad xmm6,DESCALE_P1
packssdw xmm1,xmm4 ; xmm1=data3=(30 31 32 33 34 35 36 37)
packssdw xmm0,xmm6 ; xmm0=data4=(40 41 42 43 44 45 46 47)
movdqa xmm7, XMMWORD [wk(0)] ; xmm7=(00 10 01 11 02 12 03 13)
movdqa xmm2, XMMWORD [wk(1)] ; xmm2=(04 14 05 15 06 16 07 17)
movdqa xmm4,xmm3 ; transpose coefficients(phase 1)
punpcklwd xmm3,xmm1 ; xmm3=(20 30 21 31 22 32 23 33)
punpckhwd xmm4,xmm1 ; xmm4=(24 34 25 35 26 36 27 37)
movdqa xmm6,xmm0 ; transpose coefficients(phase 1)
punpcklwd xmm0,xmm5 ; xmm0=(40 50 41 51 42 52 43 53)
punpckhwd xmm6,xmm5 ; xmm6=(44 54 45 55 46 56 47 57)
movdqa xmm1,xmm7 ; transpose coefficients(phase 2)
punpckldq xmm7,xmm3 ; xmm7=(00 10 20 30 01 11 21 31)
punpckhdq xmm1,xmm3 ; xmm1=(02 12 22 32 03 13 23 33)
movdqa xmm5,xmm2 ; transpose coefficients(phase 2)
punpckldq xmm2,xmm4 ; xmm2=(04 14 24 34 05 15 25 35)
punpckhdq xmm5,xmm4 ; xmm5=(06 16 26 36 07 17 27 37)
movdqa xmm3, XMMWORD [wk(4)] ; xmm3=(60 70 61 71 62 72 63 73)
movdqa xmm4, XMMWORD [wk(5)] ; xmm4=(64 74 65 75 66 76 67 77)
movdqa XMMWORD [wk(6)], xmm2 ; wk(6)=(04 14 24 34 05 15 25 35)
movdqa XMMWORD [wk(7)], xmm5 ; wk(7)=(06 16 26 36 07 17 27 37)
movdqa xmm2,xmm0 ; transpose coefficients(phase 2)
punpckldq xmm0,xmm3 ; xmm0=(40 50 60 70 41 51 61 71)
punpckhdq xmm2,xmm3 ; xmm2=(42 52 62 72 43 53 63 73)
movdqa xmm5,xmm6 ; transpose coefficients(phase 2)
punpckldq xmm6,xmm4 ; xmm6=(44 54 64 74 45 55 65 75)
punpckhdq xmm5,xmm4 ; xmm5=(46 56 66 76 47 57 67 77)
movdqa xmm3,xmm7 ; transpose coefficients(phase 3)
punpcklqdq xmm7,xmm0 ; xmm7=col0=(00 10 20 30 40 50 60 70)
punpckhqdq xmm3,xmm0 ; xmm3=col1=(01 11 21 31 41 51 61 71)
movdqa xmm4,xmm1 ; transpose coefficients(phase 3)
punpcklqdq xmm1,xmm2 ; xmm1=col2=(02 12 22 32 42 52 62 72)
punpckhqdq xmm4,xmm2 ; xmm4=col3=(03 13 23 33 43 53 63 73)
movdqa xmm0, XMMWORD [wk(6)] ; xmm0=(04 14 24 34 05 15 25 35)
movdqa xmm2, XMMWORD [wk(7)] ; xmm2=(06 16 26 36 07 17 27 37)
movdqa XMMWORD [wk(8)], xmm3 ; wk(8)=col1
movdqa XMMWORD [wk(9)], xmm4 ; wk(9)=col3
movdqa xmm3,xmm0 ; transpose coefficients(phase 3)
punpcklqdq xmm0,xmm6 ; xmm0=col4=(04 14 24 34 44 54 64 74)
punpckhqdq xmm3,xmm6 ; xmm3=col5=(05 15 25 35 45 55 65 75)
movdqa xmm4,xmm2 ; transpose coefficients(phase 3)
punpcklqdq xmm2,xmm5 ; xmm2=col6=(06 16 26 36 46 56 66 76)
punpckhqdq xmm4,xmm5 ; xmm4=col7=(07 17 27 37 47 57 67 77)
movdqa XMMWORD [wk(10)], xmm3 ; wk(10)=col5
movdqa XMMWORD [wk(11)], xmm4 ; wk(11)=col7
.column_end:
; -- Prefetch the next coefficient block
prefetchnta [esi + DCTSIZE2*SIZEOF_JCOEF + 0*32]
prefetchnta [esi + DCTSIZE2*SIZEOF_JCOEF + 1*32]
prefetchnta [esi + DCTSIZE2*SIZEOF_JCOEF + 2*32]
prefetchnta [esi + DCTSIZE2*SIZEOF_JCOEF + 3*32]
; ---- Pass 2: process rows from work array, store into output array.
mov eax, [original_ebp]
mov edi, JSAMPARRAY [output_buf(eax)] ; (JSAMPROW *)
mov eax, JDIMENSION [output_col(eax)]
; -- Even part
; xmm7=col0, xmm1=col2, xmm0=col4, xmm2=col6
; (Original)
; z1 = (z2 + z3) * 0.541196100;
; tmp2 = z1 + z3 * -1.847759065;
; tmp3 = z1 + z2 * 0.765366865;
;
; (This implementation)
; tmp2 = z2 * 0.541196100 + z3 * (0.541196100 - 1.847759065);
; tmp3 = z2 * (0.541196100 + 0.765366865) + z3 * 0.541196100;
movdqa xmm6,xmm1 ; xmm1=in2=z2
movdqa xmm5,xmm1
punpcklwd xmm6,xmm2 ; xmm2=in6=z3
punpckhwd xmm5,xmm2
movdqa xmm1,xmm6
movdqa xmm2,xmm5
pmaddwd xmm6,[GOTOFF(ebx,PW_F130_F054)] ; xmm6=tmp3L
pmaddwd xmm5,[GOTOFF(ebx,PW_F130_F054)] ; xmm5=tmp3H
pmaddwd xmm1,[GOTOFF(ebx,PW_F054_MF130)] ; xmm1=tmp2L
pmaddwd xmm2,[GOTOFF(ebx,PW_F054_MF130)] ; xmm2=tmp2H
movdqa xmm3,xmm7
paddw xmm7,xmm0 ; xmm7=in0+in4
psubw xmm3,xmm0 ; xmm3=in0-in4
pxor xmm4,xmm4
pxor xmm0,xmm0
punpcklwd xmm4,xmm7 ; xmm4=tmp0L
punpckhwd xmm0,xmm7 ; xmm0=tmp0H
psrad xmm4,(16-CONST_BITS) ; psrad xmm4,16 & pslld xmm4,CONST_BITS
psrad xmm0,(16-CONST_BITS) ; psrad xmm0,16 & pslld xmm0,CONST_BITS
movdqa xmm7,xmm4
paddd xmm4,xmm6 ; xmm4=tmp10L
psubd xmm7,xmm6 ; xmm7=tmp13L
movdqa xmm6,xmm0
paddd xmm0,xmm5 ; xmm0=tmp10H
psubd xmm6,xmm5 ; xmm6=tmp13H
movdqa XMMWORD [wk(0)], xmm4 ; wk(0)=tmp10L
movdqa XMMWORD [wk(1)], xmm0 ; wk(1)=tmp10H
movdqa XMMWORD [wk(2)], xmm7 ; wk(2)=tmp13L
movdqa XMMWORD [wk(3)], xmm6 ; wk(3)=tmp13H
pxor xmm5,xmm5
pxor xmm4,xmm4
punpcklwd xmm5,xmm3 ; xmm5=tmp1L
punpckhwd xmm4,xmm3 ; xmm4=tmp1H
psrad xmm5,(16-CONST_BITS) ; psrad xmm5,16 & pslld xmm5,CONST_BITS
psrad xmm4,(16-CONST_BITS) ; psrad xmm4,16 & pslld xmm4,CONST_BITS
movdqa xmm0,xmm5
paddd xmm5,xmm1 ; xmm5=tmp11L
psubd xmm0,xmm1 ; xmm0=tmp12L
movdqa xmm7,xmm4
paddd xmm4,xmm2 ; xmm4=tmp11H
psubd xmm7,xmm2 ; xmm7=tmp12H
movdqa XMMWORD [wk(4)], xmm5 ; wk(4)=tmp11L
movdqa XMMWORD [wk(5)], xmm4 ; wk(5)=tmp11H
movdqa XMMWORD [wk(6)], xmm0 ; wk(6)=tmp12L
movdqa XMMWORD [wk(7)], xmm7 ; wk(7)=tmp12H
; -- Odd part
movdqa xmm6, XMMWORD [wk(9)] ; xmm6=col3
movdqa xmm3, XMMWORD [wk(8)] ; xmm3=col1
movdqa xmm1, XMMWORD [wk(11)] ; xmm1=col7
movdqa xmm2, XMMWORD [wk(10)] ; xmm2=col5
movdqa xmm5,xmm6
movdqa xmm4,xmm3
paddw xmm5,xmm1 ; xmm5=z3
paddw xmm4,xmm2 ; xmm4=z4
; (Original)
; z5 = (z3 + z4) * 1.175875602;
; z3 = z3 * -1.961570560; z4 = z4 * -0.390180644;
; z3 += z5; z4 += z5;
;
; (This implementation)
; z3 = z3 * (1.175875602 - 1.961570560) + z4 * 1.175875602;
; z4 = z3 * 1.175875602 + z4 * (1.175875602 - 0.390180644);
movdqa xmm0,xmm5
movdqa xmm7,xmm5
punpcklwd xmm0,xmm4
punpckhwd xmm7,xmm4
movdqa xmm5,xmm0
movdqa xmm4,xmm7
pmaddwd xmm0,[GOTOFF(ebx,PW_MF078_F117)] ; xmm0=z3L
pmaddwd xmm7,[GOTOFF(ebx,PW_MF078_F117)] ; xmm7=z3H
pmaddwd xmm5,[GOTOFF(ebx,PW_F117_F078)] ; xmm5=z4L
pmaddwd xmm4,[GOTOFF(ebx,PW_F117_F078)] ; xmm4=z4H
movdqa XMMWORD [wk(10)], xmm0 ; wk(10)=z3L
movdqa XMMWORD [wk(11)], xmm7 ; wk(11)=z3H
; (Original)
; z1 = tmp0 + tmp3; z2 = tmp1 + tmp2;
; tmp0 = tmp0 * 0.298631336; tmp1 = tmp1 * 2.053119869;
; tmp2 = tmp2 * 3.072711026; tmp3 = tmp3 * 1.501321110;
; z1 = z1 * -0.899976223; z2 = z2 * -2.562915447;
; tmp0 += z1 + z3; tmp1 += z2 + z4;
; tmp2 += z2 + z3; tmp3 += z1 + z4;
;
; (This implementation)
; tmp0 = tmp0 * (0.298631336 - 0.899976223) + tmp3 * -0.899976223;
; tmp1 = tmp1 * (2.053119869 - 2.562915447) + tmp2 * -2.562915447;
; tmp2 = tmp1 * -2.562915447 + tmp2 * (3.072711026 - 2.562915447);
; tmp3 = tmp0 * -0.899976223 + tmp3 * (1.501321110 - 0.899976223);
; tmp0 += z3; tmp1 += z4;
; tmp2 += z3; tmp3 += z4;
movdqa xmm0,xmm1
movdqa xmm7,xmm1
punpcklwd xmm0,xmm3
punpckhwd xmm7,xmm3
movdqa xmm1,xmm0
movdqa xmm3,xmm7
pmaddwd xmm0,[GOTOFF(ebx,PW_MF060_MF089)] ; xmm0=tmp0L
pmaddwd xmm7,[GOTOFF(ebx,PW_MF060_MF089)] ; xmm7=tmp0H
pmaddwd xmm1,[GOTOFF(ebx,PW_MF089_F060)] ; xmm1=tmp3L
pmaddwd xmm3,[GOTOFF(ebx,PW_MF089_F060)] ; xmm3=tmp3H
paddd xmm0, XMMWORD [wk(10)] ; xmm0=tmp0L
paddd xmm7, XMMWORD [wk(11)] ; xmm7=tmp0H
paddd xmm1,xmm5 ; xmm1=tmp3L
paddd xmm3,xmm4 ; xmm3=tmp3H
movdqa XMMWORD [wk(8)], xmm0 ; wk(8)=tmp0L
movdqa XMMWORD [wk(9)], xmm7 ; wk(9)=tmp0H
movdqa xmm0,xmm2
movdqa xmm7,xmm2
punpcklwd xmm0,xmm6
punpckhwd xmm7,xmm6
movdqa xmm2,xmm0
movdqa xmm6,xmm7
pmaddwd xmm0,[GOTOFF(ebx,PW_MF050_MF256)] ; xmm0=tmp1L
pmaddwd xmm7,[GOTOFF(ebx,PW_MF050_MF256)] ; xmm7=tmp1H
pmaddwd xmm2,[GOTOFF(ebx,PW_MF256_F050)] ; xmm2=tmp2L
pmaddwd xmm6,[GOTOFF(ebx,PW_MF256_F050)] ; xmm6=tmp2H
paddd xmm0,xmm5 ; xmm0=tmp1L
paddd xmm7,xmm4 ; xmm7=tmp1H
paddd xmm2, XMMWORD [wk(10)] ; xmm2=tmp2L
paddd xmm6, XMMWORD [wk(11)] ; xmm6=tmp2H
movdqa XMMWORD [wk(10)], xmm0 ; wk(10)=tmp1L
movdqa XMMWORD [wk(11)], xmm7 ; wk(11)=tmp1H
; -- Final output stage
movdqa xmm5, XMMWORD [wk(0)] ; xmm5=tmp10L
movdqa xmm4, XMMWORD [wk(1)] ; xmm4=tmp10H
movdqa xmm0,xmm5
movdqa xmm7,xmm4
paddd xmm5,xmm1 ; xmm5=data0L
paddd xmm4,xmm3 ; xmm4=data0H
psubd xmm0,xmm1 ; xmm0=data7L
psubd xmm7,xmm3 ; xmm7=data7H
movdqa xmm1,[GOTOFF(ebx,PD_DESCALE_P2)] ; xmm1=[PD_DESCALE_P2]
paddd xmm5,xmm1
paddd xmm4,xmm1
psrad xmm5,DESCALE_P2
psrad xmm4,DESCALE_P2
paddd xmm0,xmm1
paddd xmm7,xmm1
psrad xmm0,DESCALE_P2
psrad xmm7,DESCALE_P2
packssdw xmm5,xmm4 ; xmm5=data0=(00 10 20 30 40 50 60 70)
packssdw xmm0,xmm7 ; xmm0=data7=(07 17 27 37 47 57 67 77)
movdqa xmm3, XMMWORD [wk(4)] ; xmm3=tmp11L
movdqa xmm1, XMMWORD [wk(5)] ; xmm1=tmp11H
movdqa xmm4,xmm3
movdqa xmm7,xmm1
paddd xmm3,xmm2 ; xmm3=data1L
paddd xmm1,xmm6 ; xmm1=data1H
psubd xmm4,xmm2 ; xmm4=data6L
psubd xmm7,xmm6 ; xmm7=data6H
movdqa xmm2,[GOTOFF(ebx,PD_DESCALE_P2)] ; xmm2=[PD_DESCALE_P2]
paddd xmm3,xmm2
paddd xmm1,xmm2
psrad xmm3,DESCALE_P2
psrad xmm1,DESCALE_P2
paddd xmm4,xmm2
paddd xmm7,xmm2
psrad xmm4,DESCALE_P2
psrad xmm7,DESCALE_P2
packssdw xmm3,xmm1 ; xmm3=data1=(01 11 21 31 41 51 61 71)
packssdw xmm4,xmm7 ; xmm4=data6=(06 16 26 36 46 56 66 76)
packsswb xmm5,xmm4 ; xmm5=(00 10 20 30 40 50 60 70 06 16 26 36 46 56 66 76)
packsswb xmm3,xmm0 ; xmm3=(01 11 21 31 41 51 61 71 07 17 27 37 47 57 67 77)
movdqa xmm6, XMMWORD [wk(6)] ; xmm6=tmp12L
movdqa xmm2, XMMWORD [wk(7)] ; xmm2=tmp12H
movdqa xmm1, XMMWORD [wk(10)] ; xmm1=tmp1L
movdqa xmm7, XMMWORD [wk(11)] ; xmm7=tmp1H
movdqa XMMWORD [wk(0)], xmm5 ; wk(0)=(00 10 20 30 40 50 60 70 06 16 26 36 46 56 66 76)
movdqa XMMWORD [wk(1)], xmm3 ; wk(1)=(01 11 21 31 41 51 61 71 07 17 27 37 47 57 67 77)
movdqa xmm4,xmm6
movdqa xmm0,xmm2
paddd xmm6,xmm1 ; xmm6=data2L
paddd xmm2,xmm7 ; xmm2=data2H
psubd xmm4,xmm1 ; xmm4=data5L
psubd xmm0,xmm7 ; xmm0=data5H
movdqa xmm5,[GOTOFF(ebx,PD_DESCALE_P2)] ; xmm5=[PD_DESCALE_P2]
paddd xmm6,xmm5
paddd xmm2,xmm5
psrad xmm6,DESCALE_P2
psrad xmm2,DESCALE_P2
paddd xmm4,xmm5
paddd xmm0,xmm5
psrad xmm4,DESCALE_P2
psrad xmm0,DESCALE_P2
packssdw xmm6,xmm2 ; xmm6=data2=(02 12 22 32 42 52 62 72)
packssdw xmm4,xmm0 ; xmm4=data5=(05 15 25 35 45 55 65 75)
movdqa xmm3, XMMWORD [wk(2)] ; xmm3=tmp13L
movdqa xmm1, XMMWORD [wk(3)] ; xmm1=tmp13H
movdqa xmm7, XMMWORD [wk(8)] ; xmm7=tmp0L
movdqa xmm5, XMMWORD [wk(9)] ; xmm5=tmp0H
movdqa xmm2,xmm3
movdqa xmm0,xmm1
paddd xmm3,xmm7 ; xmm3=data3L
paddd xmm1,xmm5 ; xmm1=data3H
psubd xmm2,xmm7 ; xmm2=data4L
psubd xmm0,xmm5 ; xmm0=data4H
movdqa xmm7,[GOTOFF(ebx,PD_DESCALE_P2)] ; xmm7=[PD_DESCALE_P2]
paddd xmm3,xmm7
paddd xmm1,xmm7
psrad xmm3,DESCALE_P2
psrad xmm1,DESCALE_P2
paddd xmm2,xmm7
paddd xmm0,xmm7
psrad xmm2,DESCALE_P2
psrad xmm0,DESCALE_P2
movdqa xmm5,[GOTOFF(ebx,PB_CENTERJSAMP)] ; xmm5=[PB_CENTERJSAMP]
packssdw xmm3,xmm1 ; xmm3=data3=(03 13 23 33 43 53 63 73)
packssdw xmm2,xmm0 ; xmm2=data4=(04 14 24 34 44 54 64 74)
movdqa xmm7, XMMWORD [wk(0)] ; xmm7=(00 10 20 30 40 50 60 70 06 16 26 36 46 56 66 76)
movdqa xmm1, XMMWORD [wk(1)] ; xmm1=(01 11 21 31 41 51 61 71 07 17 27 37 47 57 67 77)
packsswb xmm6,xmm2 ; xmm6=(02 12 22 32 42 52 62 72 04 14 24 34 44 54 64 74)
packsswb xmm3,xmm4 ; xmm3=(03 13 23 33 43 53 63 73 05 15 25 35 45 55 65 75)
paddb xmm7,xmm5
paddb xmm1,xmm5
paddb xmm6,xmm5
paddb xmm3,xmm5
movdqa xmm0,xmm7 ; transpose coefficients(phase 1)
punpcklbw xmm7,xmm1 ; xmm7=(00 01 10 11 20 21 30 31 40 41 50 51 60 61 70 71)
punpckhbw xmm0,xmm1 ; xmm0=(06 07 16 17 26 27 36 37 46 47 56 57 66 67 76 77)
movdqa xmm2,xmm6 ; transpose coefficients(phase 1)
punpcklbw xmm6,xmm3 ; xmm6=(02 03 12 13 22 23 32 33 42 43 52 53 62 63 72 73)
punpckhbw xmm2,xmm3 ; xmm2=(04 05 14 15 24 25 34 35 44 45 54 55 64 65 74 75)
movdqa xmm4,xmm7 ; transpose coefficients(phase 2)
punpcklwd xmm7,xmm6 ; xmm7=(00 01 02 03 10 11 12 13 20 21 22 23 30 31 32 33)
punpckhwd xmm4,xmm6 ; xmm4=(40 41 42 43 50 51 52 53 60 61 62 63 70 71 72 73)
movdqa xmm5,xmm2 ; transpose coefficients(phase 2)
punpcklwd xmm2,xmm0 ; xmm2=(04 05 06 07 14 15 16 17 24 25 26 27 34 35 36 37)
punpckhwd xmm5,xmm0 ; xmm5=(44 45 46 47 54 55 56 57 64 65 66 67 74 75 76 77)
movdqa xmm1,xmm7 ; transpose coefficients(phase 3)
punpckldq xmm7,xmm2 ; xmm7=(00 01 02 03 04 05 06 07 10 11 12 13 14 15 16 17)
punpckhdq xmm1,xmm2 ; xmm1=(20 21 22 23 24 25 26 27 30 31 32 33 34 35 36 37)
movdqa xmm3,xmm4 ; transpose coefficients(phase 3)
punpckldq xmm4,xmm5 ; xmm4=(40 41 42 43 44 45 46 47 50 51 52 53 54 55 56 57)
punpckhdq xmm3,xmm5 ; xmm3=(60 61 62 63 64 65 66 67 70 71 72 73 74 75 76 77)
pshufd xmm6,xmm7,0x4E ; xmm6=(10 11 12 13 14 15 16 17 00 01 02 03 04 05 06 07)
pshufd xmm0,xmm1,0x4E ; xmm0=(30 31 32 33 34 35 36 37 20 21 22 23 24 25 26 27)
pshufd xmm2,xmm4,0x4E ; xmm2=(50 51 52 53 54 55 56 57 40 41 42 43 44 45 46 47)
pshufd xmm5,xmm3,0x4E ; xmm5=(70 71 72 73 74 75 76 77 60 61 62 63 64 65 66 67)
mov edx, JSAMPROW [edi+0*SIZEOF_JSAMPROW]
mov esi, JSAMPROW [edi+2*SIZEOF_JSAMPROW]
movq XMM_MMWORD [edx+eax*SIZEOF_JSAMPLE], xmm7
movq XMM_MMWORD [esi+eax*SIZEOF_JSAMPLE], xmm1
mov edx, JSAMPROW [edi+4*SIZEOF_JSAMPROW]
mov esi, JSAMPROW [edi+6*SIZEOF_JSAMPROW]
movq XMM_MMWORD [edx+eax*SIZEOF_JSAMPLE], xmm4
movq XMM_MMWORD [esi+eax*SIZEOF_JSAMPLE], xmm3
mov edx, JSAMPROW [edi+1*SIZEOF_JSAMPROW]
mov esi, JSAMPROW [edi+3*SIZEOF_JSAMPROW]
movq XMM_MMWORD [edx+eax*SIZEOF_JSAMPLE], xmm6
movq XMM_MMWORD [esi+eax*SIZEOF_JSAMPLE], xmm0
mov edx, JSAMPROW [edi+5*SIZEOF_JSAMPROW]
mov esi, JSAMPROW [edi+7*SIZEOF_JSAMPROW]
movq XMM_MMWORD [edx+eax*SIZEOF_JSAMPLE], xmm2
movq XMM_MMWORD [esi+eax*SIZEOF_JSAMPLE], xmm5
pop edi
pop esi
; pop edx ; need not be preserved
; pop ecx ; unused
poppic 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