Mercurial > SDL_sound_CoreAudio
diff decoders/mpglib/decode_i386.c @ 261:9b6e82f7c853
Initial add.
author | Ryan C. Gordon <icculus@icculus.org> |
---|---|
date | Thu, 21 Feb 2002 19:46:09 +0000 |
parents | |
children | 52b9f37998db |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/decoders/mpglib/decode_i386.c Thu Feb 21 19:46:09 2002 +0000 @@ -0,0 +1,153 @@ +/* + * Mpeg Layer-1,2,3 audio decoder + * ------------------------------ + * copyright (c) 1995,1996,1997 by Michael Hipp, All rights reserved. + * 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. + */ + +#include <stdlib.h> +#include <math.h> +#include <string.h> + +#include "mpg123_sdlsound.h" +#include "mpglib_sdlsound.h" + +extern struct mpstr *gmp; + + /* old WRITE_SAMPLE */ +#define WRITE_SAMPLE(samples,sum,clip) \ + if( (sum) > 32767.0) { *(samples) = 0x7fff; (clip)++; } \ + else if( (sum) < -32768.0) { *(samples) = -0x8000; (clip)++; } \ + else { *(samples) = sum; } + +int synth_1to1_mono(real *bandPtr,unsigned char *samples,int *pnt) +{ + short samples_tmp[64]; + short *tmp1 = samples_tmp; + int i,ret; + int pnt1 = 0; + + ret = synth_1to1(bandPtr,0,(unsigned char *) samples_tmp,&pnt1); + samples += *pnt; + + for(i=0;i<32;i++) { + *( (short *) samples) = *tmp1; + samples += 2; + tmp1 += 2; + } + *pnt += 64; + + return ret; +} + + +int synth_1to1(real *bandPtr,int channel,unsigned char *out,int *pnt) +{ + static const int step = 2; + int bo; + short *samples = (short *) (out + *pnt); + + real *b0,(*buf)[0x110]; + int clip = 0; + int bo1; + + bo = gmp->synth_bo; + + if(!channel) { + bo--; + bo &= 0xf; + buf = gmp->synth_buffs[0]; + } + else { + samples++; + buf = gmp->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); + } + + gmp->synth_bo = bo; + + { + register 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 += 128; + + return clip; +} +