idct_mmx.asm

这是一个压缩解压包,用C语言进行编程的,里面有详细的源代码.

;/****************************************************************************
; *
; *  XVID MPEG-4 VIDEO CODEC
; *  - MMX and XMM forward discrete cosine transform -
; *
; *  Copyright(C) 2001 Peter Ross <[e-mail]>
; *		  2004 Andre Werthmann <[e-mail]>
; *
; *  This program is free software; you can redistribute it and/or modify it
; *  under the terms of the GNU General Public License as published by
; *  the Free Software Foundation; either version 2 of the License, or
; *  (at your option) any later version.
; *
; *  This program is distributed in the hope that it will be useful,
; *  but WITHOUT ANY WARRANTY; without even the implied warranty of
; *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; *  GNU General Public License for more details.
; *
; *  You should have received a copy of the GNU General Public License
; *  along with this program; if not, write to the Free Software
; *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
; *
; * $Id: idct_mmx.asm,v 1.1 2005/01/05 23:02:15 edgomez Exp $
; *
; ***************************************************************************/

; ****************************************************************************
;
; Originally provided by Intel at AP-922
; http://developer.intel.com/vtune/cbts/strmsimd/922down.htm
; (See more app notes at http://developer.intel.com/vtune/cbts/strmsimd/appnotes.htm)
; but in a limited edition.
; New macro implements a column part for precise iDCT
; The routine precision now satisfies IEEE standard 1180-1990.
;
; Copyright(C) 2000-2001 Peter Gubanov <[e-mail]>
; Rounding trick Copyright(C) 2000 Michel Lespinasse <[e-mail]>
;
; http://www.elecard.com/peter/idct.html
; http://www.linuxvideo.org/mpeg2dec/
;
; ***************************************************************************/
;
; These examples contain code fragments for first stage iDCT 8x8
; (for rows) and first stage DCT 8x8 (for columns)
;

BITS 64

;=============================================================================
; Macros and other preprocessor constants
;=============================================================================

%macro cglobal 1
	%ifdef PREFIX
		%ifdef MARK_FUNCS
			global _%1:function %1.endfunc-%1
			%define %1 _%1:function %1.endfunc-%1
		%else
			global _%1
			%define %1 _%1
		%endif
	%else
		%ifdef MARK_FUNCS
			global %1:function %1.endfunc-%1
		%else
			global %1
		%endif
	%endif
%endmacro

%define BITS_INV_ACC    5                         ; 4 or 5 for IEEE
%define SHIFT_INV_ROW   16 - BITS_INV_ACC
%define SHIFT_INV_COL   1 + BITS_INV_ACC
%define RND_INV_ROW     1024 * (6 - BITS_INV_ACC) ; 1 << (SHIFT_INV_ROW-1)
%define RND_INV_COL     16 * (BITS_INV_ACC - 3)   ; 1 << (SHIFT_INV_COL-1)
%define RND_INV_CORR    RND_INV_COL - 1           ; correction -1.0 and round

%define BITS_FRW_ACC    3                         ; 2 or 3 for accuracy
%define SHIFT_FRW_COL   BITS_FRW_ACC
%define SHIFT_FRW_ROW   BITS_FRW_ACC + 17
%define RND_FRW_ROW     262144*(BITS_FRW_ACC - 1) ; 1 << (SHIFT_FRW_ROW-1)

;=============================================================================
; Local Data (Read Only)
;=============================================================================

%ifdef FORMAT_COFF
SECTION .rodata
%else
SECTION .rodata align=16
%endif

;-----------------------------------------------------------------------------
; Various memory constants (trigonometric values or rounding values)
;-----------------------------------------------------------------------------

ALIGN 16
one_corr:
  dw 1, 1, 1, 1
round_inv_row:
  dd RND_INV_ROW,  RND_INV_ROW
round_inv_col:
  dw RND_INV_COL,  RND_INV_COL,  RND_INV_COL, RND_INV_COL
round_inv_corr:
  dw RND_INV_CORR, RND_INV_CORR, RND_INV_CORR, RND_INV_CORR
round_frw_row:
  dd RND_FRW_ROW,  RND_FRW_ROW
tg_1_16:
  dw 13036,  13036,  13036,  13036    ; tg * (2<<16) + 0.5
tg_2_16:
  dw 27146,  27146,  27146,  27146    ; tg * (2<<16) + 0.5
tg_3_16:
  dw -21746, -21746, -21746, -21746    ; tg * (2<<16) + 0.5
cos_4_16:
  dw -19195, -19195, -19195, -19195    ; cos * (2<<16) + 0.5
ocos_4_16:
  dw 23170,  23170,  23170,  23170    ; cos * (2<<15) + 0.5
otg_3_16:
  dw 21895, 21895, 21895, 21895       ; tg * (2<<16) + 0.5

%if SHIFT_INV_ROW == 12   ; assume SHIFT_INV_ROW == 12
rounder_0:
  dd 65536, 65536
rounder_4:
  dd 0, 0
rounder_1:
  dd 7195, 7195
rounder_7
  dd 1024, 1024
rounder_2:
  dd 4520, 4520
rounder_6:
  dd 1024, 1024
rounder_3:
  dd 2407, 2407
rounder_5:
  dd 240, 240

%elif SHIFT_INV_ROW == 11   ; assume SHIFT_INV_ROW == 11
rounder_0:
  dd 65536, 65536
rounder_4:
  dd 0, 0
rounder_1:
  dd 3597, 3597
rounder_7:
  dd 512, 512
rounder_2:
  dd 2260, 2260
rounder_6:
  dd 512, 512
rounder_3:
  dd 1203, 1203
rounder_5:
  dd 120, 120
%else

%error invalid SHIFT_INV_ROW

%endif

;-----------------------------------------------------------------------------
;
; The first stage iDCT 8x8 - inverse DCTs of rows
;
;-----------------------------------------------------------------------------
; The 8-point inverse DCT direct algorithm
;-----------------------------------------------------------------------------
;
; static const short w[32] = {
;	FIX(cos_4_16),  FIX(cos_2_16),  FIX(cos_4_16),  FIX(cos_6_16),
;	FIX(cos_4_16),  FIX(cos_6_16), -FIX(cos_4_16), -FIX(cos_2_16),
;	FIX(cos_4_16), -FIX(cos_6_16), -FIX(cos_4_16),  FIX(cos_2_16),
;	FIX(cos_4_16), -FIX(cos_2_16),  FIX(cos_4_16), -FIX(cos_6_16),
;	FIX(cos_1_16),  FIX(cos_3_16),  FIX(cos_5_16),  FIX(cos_7_16),
;	FIX(cos_3_16), -FIX(cos_7_16), -FIX(cos_1_16), -FIX(cos_5_16),
;	FIX(cos_5_16), -FIX(cos_1_16),  FIX(cos_7_16),  FIX(cos_3_16),
;	FIX(cos_7_16), -FIX(cos_5_16),  FIX(cos_3_16), -FIX(cos_1_16) };
;
; #define DCT_8_INV_ROW(x, y)
; {
; 	int a0, a1, a2, a3, b0, b1, b2, b3;
;
; 	a0 =x[0]*w[0]+x[2]*w[1]+x[4]*w[2]+x[6]*w[3];
; 	a1 =x[0]*w[4]+x[2]*w[5]+x[4]*w[6]+x[6]*w[7];
; 	a2 = x[0] * w[ 8] + x[2] * w[ 9] + x[4] * w[10] + x[6] * w[11];
; 	a3 = x[0] * w[12] + x[2] * w[13] + x[4] * w[14] + x[6] * w[15];
; 	b0 = x[1] * w[16] + x[3] * w[17] + x[5] * w[18] + x[7] * w[19];
; 	b1 = x[1] * w[20] + x[3] * w[21] + x[5] * w[22] + x[7] * w[23];
; 	b2 = x[1] * w[24] + x[3] * w[25] + x[5] * w[26] + x[7] * w[27];
; 	b3 = x[1] * w[28] + x[3] * w[29] + x[5] * w[30] + x[7] * w[31];
;
; 	y[0] = SHIFT_ROUND ( a0 + b0 );
; 	y[1] = SHIFT_ROUND ( a1 + b1 );
; 	y[2] = SHIFT_ROUND ( a2 + b2 );
; 	y[3] = SHIFT_ROUND ( a3 + b3 );
; 	y[4] = SHIFT_ROUND ( a3 - b3 );
; 	y[5] = SHIFT_ROUND ( a2 - b2 );
; 	y[6] = SHIFT_ROUND ( a1 - b1 );
; 	y[7] = SHIFT_ROUND ( a0 - b0 );
; }
;
;-----------------------------------------------------------------------------
;
; In this implementation the outputs of the iDCT-1D are multiplied
; 	for rows 0,4 - by cos_4_16,
; 	for rows 1,7 - by cos_1_16,
; 	for rows 2,6 - by cos_2_16,
; 	for rows 3,5 - by cos_3_16
; and are shifted to the left for better accuracy
;
; For the constants used,
; 	FIX(float_const) = (short) (float_const * (1<<15) + 0.5)
;
;-----------------------------------------------------------------------------

;-----------------------------------------------------------------------------
; Tables for xmm processors
;-----------------------------------------------------------------------------

; %3 for rows 0,4 - constants are multiplied by cos_4_16
tab_i_04_xmm:
  dw  16384,  21407,  16384,   8867 ; movq-> w05 w04 w01 w00
  dw  16384,   8867, -16384, -21407 ; w07 w06 w03 w02
  dw  16384,  -8867,  16384, -21407 ; w13 w12 w09 w08
  dw -16384,  21407,  16384,  -8867 ; w15 w14 w11 w10
  dw  22725,  19266,  19266,  -4520 ; w21 w20 w17 w16
  dw  12873,   4520, -22725, -12873 ; w23 w22 w19 w18
  dw  12873, -22725,   4520, -12873 ; w29 w28 w25 w24
  dw   4520,  19266,  19266, -22725 ; w31 w30 w27 w26

; %3 for rows 1,7 - constants are multiplied by cos_1_16
tab_i_17_xmm:
  dw  22725,  29692,  22725,  12299 ; movq-> w05 w04 w01 w00
  dw  22725,  12299, -22725, -29692 ; w07 w06 w03 w02
  dw  22725, -12299,  22725, -29692 ; w13 w12 w09 w08
  dw -22725,  29692,  22725, -12299 ; w15 w14 w11 w10
  dw  31521,  26722,  26722,  -6270 ; w21 w20 w17 w16
  dw  17855,   6270, -31521, -17855 ; w23 w22 w19 w18
  dw  17855, -31521,   6270, -17855 ; w29 w28 w25 w24
  dw   6270,  26722,  26722, -31521 ; w31 w30 w27 w26

; %3 for rows 2,6 - constants are multiplied by cos_2_16
tab_i_26_xmm:
  dw  21407,  27969,  21407,  11585 ; movq-> w05 w04 w01 w00
  dw  21407,  11585, -21407, -27969 ; w07 w06 w03 w02
  dw  21407, -11585,  21407, -27969 ; w13 w12 w09 w08
  dw -21407,  27969,  21407, -11585 ; w15 w14 w11 w10
  dw  29692,  25172,  25172,  -5906 ; w21 w20 w17 w16
  dw  16819,   5906, -29692, -16819 ; w23 w22 w19 w18
  dw  16819, -29692,   5906, -16819 ; w29 w28 w25 w24
  dw   5906,  25172,  25172, -29692 ; w31 w30 w27 w26

; %3 for rows 3,5 - constants are multiplied by cos_3_16
tab_i_35_xmm:
  dw  19266,  25172,  19266,  10426 ; movq-> w05 w04 w01 w00
  dw  19266,  10426, -19266, -25172 ; w07 w06 w03 w02
  dw  19266, -10426,  19266, -25172 ; w13 w12 w09 w08
  dw -19266,  25172,  19266, -10426 ; w15 w14 w11 w10
  dw  26722,  22654,  22654,  -5315 ; w21 w20 w17 w16
  dw  15137,   5315, -26722, -15137 ; w23 w22 w19 w18
  dw  15137, -26722,   5315, -15137 ; w29 w28 w25 w24