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/********************************************************************
* *
* THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. *
* *
* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
* *
* THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002 *
* BY THE Xiph.Org FOUNDATION http://www.xiph.org/ *
* *
********************************************************************
function: miscellaneous math and prototypes
********************************************************************/
#ifndef _V_RANDOM_H_
#define _V_RANDOM_H_
#include "ivorbiscodec.h"
#include "os.h"
#ifdef _LOW_ACCURACY_
# define X(n) (((((n)>>22)+1)>>1) - ((((n)>>22)+1)>>9))
# define LOOKUP_T const unsigned char
#else
# define X(n) (n)
# define LOOKUP_T const ogg_int32_t
#endif
#include "asm_arm.h"
#include <stdlib.h> /* for abs() */
#ifndef _V_WIDE_MATH
#define _V_WIDE_MATH
#ifndef _LOW_ACCURACY_
/* 64 bit multiply */
#if !(defined WIN32 && defined WINCE)
#include <sys/types.h>
#endif
#if BYTE_ORDER==LITTLE_ENDIAN
union magic {
struct {
ogg_int32_t lo;
ogg_int32_t hi;
} halves;
ogg_int64_t whole;
};
#elif BYTE_ORDER==BIG_ENDIAN
union magic {
struct {
ogg_int32_t hi;
ogg_int32_t lo;
} halves;
ogg_int64_t whole;
};
#endif
STIN ogg_int32_t MULT32(ogg_int32_t x, ogg_int32_t y) {
union magic magic;
magic.whole = (ogg_int64_t)x * y;
return magic.halves.hi;
}
STIN ogg_int32_t MULT31(ogg_int32_t x, ogg_int32_t y) {
return MULT32(x,y)<<1;
}
STIN ogg_int32_t MULT31_SHIFT15(ogg_int32_t x, ogg_int32_t y) {
union magic magic;
magic.whole = (ogg_int64_t)x * y;
return ((ogg_uint32_t)(magic.halves.lo)>>15) | ((magic.halves.hi)<<17);
}
#else
/* 32 bit multiply, more portable but less accurate */
/*
* Note: Precision is biased towards the first argument therefore ordering
* is important. Shift values were chosen for the best sound quality after
* many listening tests.
*/
/*
* For MULT32 and MULT31: The second argument is always a lookup table
* value already preshifted from 31 to 8 bits. We therefore take the
* opportunity to save on text space and use unsigned char for those
* tables in this case.
*/
STIN ogg_int32_t MULT32(ogg_int32_t x, ogg_int32_t y) {
return (x >> 9) * y; /* y preshifted >>23 */
}
STIN ogg_int32_t MULT31(ogg_int32_t x, ogg_int32_t y) {
return (x >> 8) * y; /* y preshifted >>23 */
}
STIN ogg_int32_t MULT31_SHIFT15(ogg_int32_t x, ogg_int32_t y) {
return (x >> 6) * y; /* y preshifted >>9 */
}
#endif
/*
* This should be used as a memory barrier, forcing all cached values in
* registers to wr writen back to memory. Might or might not be beneficial
* depending on the architecture and compiler.
*/
#define MB()
/*
* The XPROD functions are meant to optimize the cross products found all
* over the place in mdct.c by forcing memory operation ordering to avoid
* unnecessary register reloads as soon as memory is being written to.
* However this is only beneficial on CPUs with a sane number of general
* purpose registers which exclude the Intel x86. On Intel, better let the
* compiler actually reload registers directly from original memory by using
* macros.
*/
#ifdef __i386__
#define XPROD32(_a, _b, _t, _v, _x, _y) \
{ *(_x)=MULT32(_a,_t)+MULT32(_b,_v); \
*(_y)=MULT32(_b,_t)-MULT32(_a,_v); }
#define XPROD31(_a, _b, _t, _v, _x, _y) \
{ *(_x)=MULT31(_a,_t)+MULT31(_b,_v); \
*(_y)=MULT31(_b,_t)-MULT31(_a,_v); }
#define XNPROD31(_a, _b, _t, _v, _x, _y) \
{ *(_x)=MULT31(_a,_t)-MULT31(_b,_v); \
*(_y)=MULT31(_b,_t)+MULT31(_a,_v); }
#else
STIN void XPROD32(ogg_int32_t a, ogg_int32_t b,
ogg_int32_t t, ogg_int32_t v,
ogg_int32_t *x, ogg_int32_t *y)
{
*x = MULT32(a, t) + MULT32(b, v);
*y = MULT32(b, t) - MULT32(a, v);
}
STIN void XPROD31(ogg_int32_t a, ogg_int32_t b,
ogg_int32_t t, ogg_int32_t v,
ogg_int32_t *x, ogg_int32_t *y)
{
*x = MULT31(a, t) + MULT31(b, v);
*y = MULT31(b, t) - MULT31(a, v);
}
STIN void XNPROD31(ogg_int32_t a, ogg_int32_t b,
ogg_int32_t t, ogg_int32_t v,
ogg_int32_t *x, ogg_int32_t *y)
{
*x = MULT31(a, t) - MULT31(b, v);
*y = MULT31(b, t) + MULT31(a, v);
}
#endif
#endif
#ifndef _V_CLIP_MATH
#define _V_CLIP_MATH
STIN ogg_int32_t CLIP_TO_15(ogg_int32_t x) {
int ret=x;
ret-= ((x<=32767)-1)&(x-32767);
ret-= ((x>=-32768)-1)&(x+32768);
return(ret);
}
#endif
STIN ogg_int32_t VFLOAT_MULT(ogg_int32_t a,ogg_int32_t ap,
ogg_int32_t b,ogg_int32_t bp,
ogg_int32_t *p){
if(a && b){
#ifndef _LOW_ACCURACY_
*p=ap+bp+32;
return MULT32(a,b);
#else
*p=ap+bp+31;
return (a>>15)*(b>>16);
#endif
}else
return 0;
}
int _ilog(unsigned int);
STIN ogg_int32_t VFLOAT_MULTI(ogg_int32_t a,ogg_int32_t ap,
ogg_int32_t i,
ogg_int32_t *p){
int ip=_ilog(abs(i))-31;
return VFLOAT_MULT(a,ap,i<<-ip,ip,p);
}
STIN ogg_int32_t VFLOAT_ADD(ogg_int32_t a,ogg_int32_t ap,
ogg_int32_t b,ogg_int32_t bp,
ogg_int32_t *p){
if(!a){
*p=bp;
return b;
}else if(!b){
*p=ap;
return a;
}
/* yes, this can leak a bit. */
if(ap>bp){
int shift=ap-bp+1;
*p=ap+1;
a>>=1;
if(shift<32){
b=(b+(1<<(shift-1)))>>shift;
}else{
b=0;
}
}else{
int shift=bp-ap+1;
*p=bp+1;
b>>=1;
if(shift<32){
a=(a+(1<<(shift-1)))>>shift;
}else{
a=0;
}
}
a+=b;
if((a&0xc0000000)==0xc0000000 ||
(a&0xc0000000)==0){
a<<=1;
(*p)--;
}
return(a);
}
#endif
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