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