?? decode_i386.c
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/* * Mpeg Layer-1,2,3 audio decoder * ------------------------------ * copyright (c) 1995,1996,1997 by Michael Hipp, All rights reserved. * modified by Aleksander Korzynski (Olcios) '2003 * See also 'README' * * slighlty optimized for machines without autoincrement/decrement. * The performance is highly compiler dependend. Maybe * the decode.c version for 'normal' processor may be faster * even for Intel processors. *//* $Id: decode_i386.c,v 1.17 2004/04/14 22:15:44 robert Exp $ */#ifdef HAVE_CONFIG_H#include <config.h>#endif#ifdef STDC_HEADERS# include <stdlib.h># include <string.h>#else# ifndef HAVE_STRCHR# define strchr index# define strrchr rindex# endifchar *strchr (), *strrchr ();# ifndef HAVE_MEMCPY# define memcpy(d, s, n) bcopy ((s), (d), (n))# define memmove(d, s, n) bcopy ((s), (d), (n))# endif#endif#if defined(__riscos__) && defined(FPA10)#include "ymath.h"#else#include <math.h>#endif#include "decode_i386.h"#include "dct64_i386.h"#include "tabinit.h"#ifdef WITH_DMALLOC#include <dmalloc.h>#endif /* old WRITE_SAMPLE_CLIPPED */#define WRITE_SAMPLE_CLIPPED(samples,sum,clip) \ if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \ else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \ else { *(samples) = ((sum)>0 ? (sum)+0.5 : (sum)-0.5) ; }#define WRITE_SAMPLE_UNCLIPPED(samples,sum,clip) \ *samples = sum; /* versions: clipped (when TYPE == short) and unclipped (when TYPE == real) of synth_1to1_mono* functions */#define SYNTH_1TO1_MONO_CLIPCHOICE(TYPE,SYNTH_1TO1) \ TYPE samples_tmp[64]; \ TYPE *tmp1 = samples_tmp; \ int i,ret; \ int pnt1 = 0; \ \ ret = SYNTH_1TO1 (mp,bandPtr,0,(unsigned char *) samples_tmp,&pnt1); \ out += *pnt; \ \ for(i=0;i<32;i++) { \ *( (TYPE *) out) = *tmp1; \ out += sizeof(TYPE); \ tmp1 += 2; \ } \ *pnt += 32*sizeof(TYPE); \ \ return ret; int synth_1to1_mono(PMPSTR mp, real *bandPtr,unsigned char *out,int *pnt){ SYNTH_1TO1_MONO_CLIPCHOICE(short,synth_1to1)}int synth_1to1_mono_unclipped(PMPSTR mp, real *bandPtr, unsigned char *out,int *pnt){ SYNTH_1TO1_MONO_CLIPCHOICE(real,synth_1to1_unclipped)}/* versions: clipped (when TYPE == short) and unclipped (when TYPE == real) of synth_1to1* functions */#define SYNTH_1TO1_CLIPCHOICE(TYPE,WRITE_SAMPLE) \ static const int step = 2; \ int bo; \ TYPE *samples = (TYPE *) (out + *pnt); \ \ real *b0,(*buf)[0x110]; \ int clip = 0; \ int bo1; \ \ bo = mp->synth_bo; \ \ if(!channel) { \ bo--; \ bo &= 0xf; \ buf = mp->synth_buffs[0]; \ } \ else { \ samples++; \ buf = mp->synth_buffs[1]; \ } \ \ if(bo & 0x1) { \ b0 = buf[0]; \ bo1 = bo; \ dct64(buf[1]+((bo+1)&0xf),buf[0]+bo,bandPtr); \ } \ else { \ b0 = buf[1]; \ bo1 = bo+1; \ dct64(buf[0]+bo,buf[1]+bo+1,bandPtr); \ } \ \ mp->synth_bo = bo; \ \ { \ int j; \ real *window = decwin + 16 - bo1; \ \ for (j=16;j;j--,b0+=0x10,window+=0x20,samples+=step) \ { \ real sum; \ sum = window[0x0] * b0[0x0]; \ sum -= window[0x1] * b0[0x1]; \ sum += window[0x2] * b0[0x2]; \ sum -= window[0x3] * b0[0x3]; \ sum += window[0x4] * b0[0x4]; \ sum -= window[0x5] * b0[0x5]; \ sum += window[0x6] * b0[0x6]; \ sum -= window[0x7] * b0[0x7]; \ sum += window[0x8] * b0[0x8]; \ sum -= window[0x9] * b0[0x9]; \ sum += window[0xA] * b0[0xA]; \ sum -= window[0xB] * b0[0xB]; \ sum += window[0xC] * b0[0xC]; \ sum -= window[0xD] * b0[0xD]; \ sum += window[0xE] * b0[0xE]; \ sum -= window[0xF] * b0[0xF]; \ \ WRITE_SAMPLE (samples,sum,clip); \ } \ \ { \ real sum; \ sum = window[0x0] * b0[0x0]; \ sum += window[0x2] * b0[0x2]; \ sum += window[0x4] * b0[0x4]; \ sum += window[0x6] * b0[0x6]; \ sum += window[0x8] * b0[0x8]; \ sum += window[0xA] * b0[0xA]; \ sum += window[0xC] * b0[0xC]; \ sum += window[0xE] * b0[0xE]; \ WRITE_SAMPLE (samples,sum,clip); \ b0-=0x10,window-=0x20,samples+=step; \ } \ window += bo1<<1; \ \ for (j=15;j;j--,b0-=0x10,window-=0x20,samples+=step) \ { \ real sum; \ sum = -window[-0x1] * b0[0x0]; \ sum -= window[-0x2] * b0[0x1]; \ sum -= window[-0x3] * b0[0x2]; \ sum -= window[-0x4] * b0[0x3]; \ sum -= window[-0x5] * b0[0x4]; \ sum -= window[-0x6] * b0[0x5]; \ sum -= window[-0x7] * b0[0x6]; \ sum -= window[-0x8] * b0[0x7]; \ sum -= window[-0x9] * b0[0x8]; \ sum -= window[-0xA] * b0[0x9]; \ sum -= window[-0xB] * b0[0xA]; \ sum -= window[-0xC] * b0[0xB]; \ sum -= window[-0xD] * b0[0xC]; \ sum -= window[-0xE] * b0[0xD]; \ sum -= window[-0xF] * b0[0xE]; \ sum -= window[-0x0] * b0[0xF]; \ \ WRITE_SAMPLE (samples,sum,clip); \ } \ } \ *pnt += 64*sizeof(TYPE); \ \ return clip; int synth_1to1(PMPSTR mp, real *bandPtr,int channel,unsigned char *out, int *pnt){ SYNTH_1TO1_CLIPCHOICE(short,WRITE_SAMPLE_CLIPPED)}int synth_1to1_unclipped(PMPSTR mp, real *bandPtr,int channel, unsigned char *out, int *pnt){ SYNTH_1TO1_CLIPCHOICE(real,WRITE_SAMPLE_UNCLIPPED)}?? 快捷鍵說明
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