/********************************************************************

 *                                                                  *

 * 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.       *

 *                                                                  *

 * 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 "asm_arm.h"

#ifndef _V_WIDE_MATH

#define _V_WIDE_MATH

#ifndef  _LOW_ACCURACY_

/* 64 bit multiply */

#include <sys/types.h>

#if BYTE_ORDER==LITTLE_ENDIAN

union magic {

  struct {

    ogg_int32_t lo;

    ogg_int32_t hi;

  } halves;

  ogg_int64_t whole;

};

#endif 

#if BYTE_ORDER==BIG_ENDIAN

  struct {

    ogg_int32_t hi;

    ogg_int32_t lo;

  } halves;

  ogg_int64_t whole;

#endif

  union magic magic;

  magic.whole = (ogg_int64_t)x * y;

  return magic.halves.hi;

}

  return MULT32(x,y)<<1;

}

  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.

 */

  return (x >> 9) * y;  /* y preshifted >>23 */

}

  return (x >> 8) * y;  /* y preshifted >>23 */

}

  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

			   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);

}

			   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);

}

			    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

  int ret=x;

  ret-= ((x<=32767)-1)&(x-32767);

  ret-= ((x>=-32768)-1)&(x+32768);

  return(ret);

}

#endif

#endif