#include "stdafx.h"
#pragma hdrstop
/***************************************************************************
*
* INTEL Corporation Proprietary Information
*
*
* Copyright (c) 1996 Intel Corporation.
* All rights reserved.
*
***************************************************************************
*/
/*
* jfdctfst.c
*
* Copyright (C) 1994-1996, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains a fast, not so accurate integer implementation of the
* forward DCT (Discrete Cosine Transform).
*
* A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
* on each column. Direct algorithms are also available, but they are
* much more complex and seem not to be any faster when reduced to code.
*
* This implementation is based on Arai, Agui, and Nakajima's algorithm for
* scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in
* Japanese, but the algorithm is described in the Pennebaker & Mitchell
* JPEG textbook (see REFERENCES section in file README). The following code
* is based directly on figure 4-8 in P&M.
* While an 8-point DCT cannot be done in less than 11 multiplies, it is
* possible to arrange the computation so that many of the multiplies are
* simple scalings of the final outputs. These multiplies can then be
* folded into the multiplications or divisions by the JPEG quantization
* table entries. The AA&N method leaves only 5 multiplies and 29 adds
* to be done in the DCT itself.
* The primary disadvantage of this method is that with fixed-point math,
* accuracy is lost due to imprecise representation of the scaled
* quantization values. The smaller the quantization table entry, the less
* precise the scaled value, so this implementation does worse with high-
* quality-setting files than with low-quality ones.
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "jdct.h" /* Private declarations for DCT subsystem */
#ifdef DCT_IFAST_SUPPORTED
/*
* This module is specialized to the case DCTSIZE = 8.
*/
#if DCTSIZE != 8
Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
#endif
/* Scaling decisions are generally the same as in the LL&M algorithm;
* see jfdctint.c for more details. However, we choose to descale
* (right shift) multiplication products as soon as they are formed,
* rather than carrying additional fractional bits into subsequent additions.
* This compromises accuracy slightly, but it lets us save a few shifts.
* More importantly, 16-bit arithmetic is then adequate (for 8-bit samples)
* everywhere except in the multiplications proper; this saves a good deal
* of work on 16-bit-int machines.
*
* Again to save a few shifts, the intermediate results between pass 1 and
* pass 2 are not upscaled, but are represented only to integral precision.
*
* A final compromise is to represent the multiplicative constants to only
* 8 fractional bits, rather than 13. This saves some shifting work on some
* machines, and may also reduce the cost of multiplication (since there
* are fewer one-bits in the constants).
*/
#define CONST_BITS 8
/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
* causing a lot of useless floating-point operations at run time.
* To get around this we use the following pre-calculated constants.
* If you change CONST_BITS you may want to add appropriate values.
* (With a reasonable C compiler, you can just rely on the FIX() macro...)
*/
#if CONST_BITS == 8
#define FIX_0_382683433 98 /* FIX(0.382683433) */
#define FIX_0_541196100 139 /* FIX(0.541196100) */
#define FIX_0_707106781 181 /* FIX(0.707106781) */
#define FIX_1_306562965 334 /* FIX(1.306562965) */
#else
#define FIX_0_382683433 FIX(0.382683433)
#define FIX_0_541196100 FIX(0.541196100)
#define FIX_0_707106781 FIX(0.707106781)
#define FIX_1_306562965 FIX(1.306562965)
#endif
/* We can gain a little more speed, with a further compromise in accuracy,
* by omitting the addition in a descaling shift. This yields an incorrectly
* rounded result half the time...
*/
// The assembly version makes this compromise.
//#ifndef USE_ACCURATE_ROUNDING
//#undef DESCALE
//#define DESCALE(x,n) RIGHT_SHIFT(x, n)
//#endif
#define DCTWIDTH 32
#define DATASIZE 4
/* Multiply a DCTELEM variable by an INT32 constant, and immediately
* descale to yield a DCTELEM result.
*/
#define MULTIPLY(var,const) ((DCTELEM) DESCALE((var) * (const), CONST_BITS))
#if _MSC_FULL_VER >= 13008827 && defined(_M_IX86)
#pragma warning(push)
#pragma warning(disable:4731) // EBP modified with inline asm
#endif
/*
* Perform the forward DCT on one block of samples.
*/
GLOBAL(void)
pfdct8x8aan (DCTELEM * data)
{
DCTELEM tmp4, tmp6, tmp7;
int counter;
__asm{
/* Pass 1: process rows. */
// dataptr = data;
mov esi, [data]
mov counter, 8
// for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
// tmp0 = dataptr[0] + dataptr[7];
// tmp7 = dataptr[0] - dataptr[7];
// tmp1 = dataptr[1] + dataptr[6];
// tmp6 = dataptr[1] - dataptr[6];
// tmp2 = dataptr[2] + dataptr[5];
// tmp5 = dataptr[2] - dataptr[5];
// tmp3 = dataptr[3] + dataptr[4];
// tmp4 = dataptr[3] - dataptr[4];
StartRow:
mov eax, [esi][DATASIZE*0]
mov ebx, [esi][DATASIZE*7]
mov edx, eax
add eax, ebx ; eax = tmp0
sub edx, ebx ; edx = tmp7
mov ebx, [esi][DATASIZE*3]
mov ecx, [esi][DATASIZE*4]
mov edi, ebx
add ebx, ecx ; ebx = tmp3
sub edi, ecx ; edi = tmp4
mov tmp4, edi
mov tmp7, edx
/* Even part */
// tmp10 = tmp0 + tmp3;
// tmp13 = tmp0 - tmp3;
// tmp11 = tmp1 + tmp2;
// tmp12 = tmp1 - tmp2;
mov ecx, eax
add eax, ebx ; eax = tmp10
sub ecx, ebx ; ecx = tmp13
mov edx, [esi][DATASIZE*1]
mov edi, [esi][DATASIZE*6]
mov ebx, edx
add edx, edi ; edx = tmp1
sub ebx, edi ; ebx = tmp6
mov tmp6, ebx
push ebp
mov edi, [esi][DATASIZE*2]
mov ebp, [esi][DATASIZE*5]
mov ebx, edi
add edi, ebp ; edi = tmp2
sub ebx, ebp ; ebx = tmp5
mov ebp, edx
add edx, edi ; edx = tmp11
sub ebp, edi ; ebp = tmp12
// dataptr[0] = tmp10 + tmp11; /* phase 3 */
// dataptr[4] = tmp10 - tmp11;
mov edi, eax
add eax, edx ; eax = tmp10 + tmp11
sub edi, edx ; edi = tmp10 - tmp11
add ebp, ecx ; ebp = tmp12 + tmp13
// z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
imul ebp, FIX_0_707106781 ; ebp = z1
sar ebp, 8
mov [esi][DATASIZE*0], eax
// dataptr[2] = tmp13 + z1; /* phase 5 */
// dataptr[6] = tmp13 - z1;
mov eax, ecx
add ecx, ebp
sub eax, ebp
pop ebp
mov [esi][DATASIZE*4], edi
mov [esi][DATASIZE*2], ecx
mov [esi][DATASIZE*6], eax
mov edi, tmp4
/* Odd part */
// tmp10 = tmp4 + tmp5; /* phase 2 */
// tmp11 = tmp5 + tmp6;
// tmp12 = tmp6 + tmp7;
mov ecx, tmp6
mov edx, tmp7
add edi, ebx ; edi = tmp10
add ebx, ecx ; ebx = tmp11
// z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
// z11 = tmp7 + z3; /* phase 5 */
// z13 = tmp7 - z3;
imul ebx, FIX_0_707106781 ; ebx = z3
sar ebx, 8
add ecx, edx ; ecx = tmp12
mov eax, edx
add edx, ebx ; edx = z11
sub eax, ebx ; eax = z13
mov ebx, edi
/* The rotator is modified from fig 4-8 to avoid extra negations. */
// z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
// z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
// z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
imul ebx, FIX_0_541196100
sar ebx, 8
sub edi, ecx ; edi = tmp10 - tmp12
imul edi, FIX_0_382683433 ; edi = z5
sar edi, 8
add esi, 32
imul ecx, FIX_1_306562965
sar ecx, 8
add ebx, edi ; ebx = z2
add ecx, edi ; ecx = z4
mov edi, eax
// dataptr[5] = z13 + z2; /* phase 6 */
// dataptr[3] = z13 - z2;
// dataptr[1] = z11 + z4;
// dataptr[7] = z11 - z4;
add eax, ebx ; eax = z13 + z2
sub edi, ebx ; edi = z13 - z2
mov [esi][DATASIZE*5-32], eax
mov ebx, edx
mov [esi][DATASIZE*3-32], edi
add edx, ecx ; edx = z11 + z4
mov [esi][DATASIZE*1-32], edx
sub ebx, ecx ; ebx = z11 - z4
mov ecx, counter
mov [esi][DATASIZE*7-32], ebx
dec ecx
mov counter, ecx
jnz StartRow
// dataptr += DCTSIZE; /* advance pointer to next row */
// }
/* Pass 2: process columns.*/
// dataptr = data;
mov esi, [data]
mov counter, 8
// for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
// tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
// tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
// tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
// tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
// tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
// tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
// tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
// tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];
StartCol:
mov eax, [esi][DCTWIDTH*0]
mov ebx, [esi][DCTWIDTH*7]
mov edx, eax
add eax, ebx ; eax = tmp0
sub edx, ebx ; edx = tmp7
mov ebx, [esi][DCTWIDTH*3]
mov ecx, [esi][DCTWIDTH*4]
mov edi, ebx
add ebx, ecx ; ebx = tmp3
sub edi, ecx ; edi = tmp4
mov tmp4, edi
mov tmp7, edx
/* Even part */
// tmp10 = tmp0 + tmp3;
// tmp13 = tmp0 - tmp3;
// tmp11 = tmp1 + tmp2;
// tmp12 = tmp1 - tmp2;
mov ecx, eax
add eax, ebx ; eax = tmp10
sub ecx, ebx ; ecx = tmp13
mov edx, [esi][DCTWIDTH*1]
mov edi, [esi][DCTWIDTH*6]
mov ebx, edx
add edx, edi ; edx = tmp1
sub ebx, edi ; ebx = tmp6
mov tmp6, ebx
push ebp
mov edi, [esi][DCTWIDTH*2]
mov ebp, [esi][DCTWIDTH*5]
mov ebx, edi
add edi, ebp ; edi = tmp2
sub ebx, ebp ; ebx = tmp5
mov ebp, edx
add edx, edi ; edx = tmp11
sub ebp, edi ; ebp = tmp12
// dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */
// dataptr[DCTSIZE*4] = tmp10 - tmp11;
mov edi, eax
add eax, edx ; eax = tmp10 + tmp11
sub edi, edx ; edi = tmp10 - tmp11
add ebp, ecx ; ebp = tmp12 + tmp13
// z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
imul ebp, FIX_0_707106781 ; ebp = z1
sar ebp, 8
mov [esi][DCTWIDTH*0], eax
// dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */
// dataptr[DCTSIZE*6] = tmp13 - z1;
mov eax, ecx
add ecx, ebp
sub eax, ebp
pop ebp
mov [esi][DCTWIDTH*4], edi
mov [esi][DCTWIDTH*2], ecx
mov [esi][DCTWIDTH*6], eax
mov edi, tmp4
/* Odd part */
// tmp10 = tmp4 + tmp5; /* phase 2 */
// tmp11 = tmp5 + tmp6;
// tmp12 = tmp6 + tmp7;
mov ecx, tmp6
mov edx, tmp7
add edi, ebx ; edi = tmp10
add ebx, ecx ; ebx = tmp11
// z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
// z11 = tmp7 + z3; /* phase 5 */
// z13 = tmp7 - z3;
imul ebx, FIX_0_707106781 ; ebx = z3
sar ebx, 8
add ecx, edx ; ecx = tmp12
mov eax, edx
add edx, ebx ; edx = z11
sub eax, ebx ; eax = z13
mov ebx, edi
/* The rotator is modified from fig 4-8 to avoid extra negations. */
// z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
// z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
// z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
imul ebx, FIX_0_541196100
sar ebx, 8
sub edi, ecx ; edi = tmp10 - tmp12
imul edi, FIX_0_382683433 ; edi = z5
sar edi, 8
add esi, 4
imul ecx, FIX_1_306562965
sar ecx, 8
add ebx, edi ; ebx = z2
add ecx, edi ; ecx = z4
mov edi, eax
// dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */
// dataptr[DCTSIZE*3] = z13 - z2;
// dataptr[DCTSIZE*1] = z11 + z4;
// dataptr[DCTSIZE*7] = z11 - z4;
add eax, ebx ; eax = z13 + z2
sub edi, ebx ; edi = z13 - z2
mov [esi][DCTWIDTH*5-4], eax
mov ebx, edx
mov [esi][DCTWIDTH*3-4], edi
add edx, ecx ; edx = z11 + z4
mov [esi][DCTWIDTH*1-4], edx
sub ebx, ecx ; ebx = z11 - z4
mov ecx, counter
mov [esi][DCTWIDTH*7-4], ebx
dec ecx
mov counter, ecx
jnz StartCol
} //end asm
// dataptr++; /* advance pointer to next column */
// }
}
#if _MSC_FULL_VER >= 13008827
#pragma warning(pop)
#endif
#endif /* DCT_ISLOW_SUPPORTED */