mirror of
https://github.com/ekeeke/Genesis-Plus-GX.git
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249 lines
5.7 KiB
C
249 lines
5.7 KiB
C
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/********************************************************************
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* *
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* THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. *
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* *
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* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
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* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
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* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
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* *
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* THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002 *
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* BY THE Xiph.Org FOUNDATION http://www.xiph.org/ *
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* *
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********************************************************************
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function: miscellaneous math and prototypes
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********************************************************************/
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#ifndef _V_RANDOM_H_
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#define _V_RANDOM_H_
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#include "ivorbiscodec.h"
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#include "os.h"
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#include "asm_arm.h"
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#include <stdlib.h> /* for abs() */
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#ifdef GEKKO
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#include <gctypes.h>
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#endif
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#ifndef _V_WIDE_MATH
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#define _V_WIDE_MATH
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#ifndef _LOW_ACCURACY_
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/* 64 bit multiply */
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#if !(defined WIN32 && defined WINCE)
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#include <sys/types.h>
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#endif
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#if BYTE_ORDER==LITTLE_ENDIAN
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union magic {
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struct {
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ogg_int32_t lo;
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ogg_int32_t hi;
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} halves;
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ogg_int64_t whole;
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};
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#endif
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#if BYTE_ORDER==BIG_ENDIAN
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union magic {
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struct {
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ogg_int32_t hi;
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ogg_int32_t lo;
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} halves;
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ogg_int64_t whole;
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};
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#endif
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STIN ogg_int32_t MULT32(ogg_int32_t x, ogg_int32_t y) {
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union magic magic;
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magic.whole = (ogg_int64_t)x * y;
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return magic.halves.hi;
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}
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STIN ogg_int32_t MULT31(ogg_int32_t x, ogg_int32_t y) {
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return MULT32(x,y)<<1;
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}
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STIN ogg_int32_t MULT31_SHIFT15(ogg_int32_t x, ogg_int32_t y) {
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union magic magic;
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magic.whole = (ogg_int64_t)x * y;
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return ((ogg_uint32_t)(magic.halves.lo)>>15) | ((magic.halves.hi)<<17);
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}
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#else
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/* 32 bit multiply, more portable but less accurate */
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/*
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* Note: Precision is biased towards the first argument therefore ordering
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* is important. Shift values were chosen for the best sound quality after
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* many listening tests.
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*/
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/*
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* For MULT32 and MULT31: The second argument is always a lookup table
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* value already preshifted from 31 to 8 bits. We therefore take the
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* opportunity to save on text space and use unsigned char for those
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* tables in this case.
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*/
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STIN ogg_int32_t MULT32(ogg_int32_t x, ogg_int32_t y) {
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return (x >> 9) * y; /* y preshifted >>23 */
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}
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STIN ogg_int32_t MULT31(ogg_int32_t x, ogg_int32_t y) {
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return (x >> 8) * y; /* y preshifted >>23 */
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}
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STIN ogg_int32_t MULT31_SHIFT15(ogg_int32_t x, ogg_int32_t y) {
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return (x >> 6) * y; /* y preshifted >>9 */
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}
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#endif
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/*
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* This should be used as a memory barrier, forcing all cached values in
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* registers to wr writen back to memory. Might or might not be beneficial
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* depending on the architecture and compiler.
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*/
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#define MB()
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/*
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* The XPROD functions are meant to optimize the cross products found all
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* over the place in mdct.c by forcing memory operation ordering to avoid
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* unnecessary register reloads as soon as memory is being written to.
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* However this is only beneficial on CPUs with a sane number of general
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* purpose registers which exclude the Intel x86. On Intel, better let the
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* compiler actually reload registers directly from original memory by using
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* macros.
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*/
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#ifdef __i386__
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#define XPROD32(_a, _b, _t, _v, _x, _y) \
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{ *(_x)=MULT32(_a,_t)+MULT32(_b,_v); \
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*(_y)=MULT32(_b,_t)-MULT32(_a,_v); }
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#define XPROD31(_a, _b, _t, _v, _x, _y) \
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{ *(_x)=MULT31(_a,_t)+MULT31(_b,_v); \
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*(_y)=MULT31(_b,_t)-MULT31(_a,_v); }
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#define XNPROD31(_a, _b, _t, _v, _x, _y) \
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{ *(_x)=MULT31(_a,_t)-MULT31(_b,_v); \
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*(_y)=MULT31(_b,_t)+MULT31(_a,_v); }
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#else
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STIN void XPROD32(ogg_int32_t a, ogg_int32_t b,
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ogg_int32_t t, ogg_int32_t v,
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ogg_int32_t *x, ogg_int32_t *y)
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{
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*x = MULT32(a, t) + MULT32(b, v);
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*y = MULT32(b, t) - MULT32(a, v);
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}
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STIN void XPROD31(ogg_int32_t a, ogg_int32_t b,
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ogg_int32_t t, ogg_int32_t v,
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ogg_int32_t *x, ogg_int32_t *y)
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{
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*x = MULT31(a, t) + MULT31(b, v);
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*y = MULT31(b, t) - MULT31(a, v);
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}
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STIN void XNPROD31(ogg_int32_t a, ogg_int32_t b,
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ogg_int32_t t, ogg_int32_t v,
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ogg_int32_t *x, ogg_int32_t *y)
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{
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*x = MULT31(a, t) - MULT31(b, v);
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*y = MULT31(b, t) + MULT31(a, v);
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}
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#endif
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#endif
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#ifndef _V_CLIP_MATH
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#define _V_CLIP_MATH
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STIN ogg_int32_t CLIP_TO_15(ogg_int32_t x) {
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int ret=x;
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ret-= ((x<=32767)-1)&(x-32767);
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ret-= ((x>=-32768)-1)&(x+32768);
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return(ret);
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}
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#endif
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STIN ogg_int32_t VFLOAT_MULT(ogg_int32_t a,ogg_int32_t ap,
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ogg_int32_t b,ogg_int32_t bp,
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ogg_int32_t *p){
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if(a && b){
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#ifndef _LOW_ACCURACY_
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*p=ap+bp+32;
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return MULT32(a,b);
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#else
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*p=ap+bp+31;
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return (a>>15)*(b>>16);
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#endif
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}else
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return 0;
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}
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int _ilog(unsigned int);
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STIN ogg_int32_t VFLOAT_MULTI(ogg_int32_t a,ogg_int32_t ap,
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ogg_int32_t i,
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ogg_int32_t *p){
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int ip=_ilog(abs(i))-31;
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return VFLOAT_MULT(a,ap,i<<-ip,ip,p);
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}
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STIN ogg_int32_t VFLOAT_ADD(ogg_int32_t a,ogg_int32_t ap,
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ogg_int32_t b,ogg_int32_t bp,
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ogg_int32_t *p){
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if(!a){
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*p=bp;
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return b;
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}else if(!b){
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*p=ap;
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return a;
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}
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/* yes, this can leak a bit. */
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if(ap>bp){
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int shift=ap-bp+1;
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*p=ap+1;
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a>>=1;
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if(shift<32){
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b=(b+(1<<(shift-1)))>>shift;
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}else{
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b=0;
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}
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}else{
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int shift=bp-ap+1;
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*p=bp+1;
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b>>=1;
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if(shift<32){
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a=(a+(1<<(shift-1)))>>shift;
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}else{
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a=0;
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}
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}
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a+=b;
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if((a&0xc0000000)==0xc0000000 ||
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(a&0xc0000000)==0){
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a<<=1;
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(*p)--;
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}
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return(a);
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}
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#endif
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