assembly.h

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/**************************************************************************************
 * Fixed-point MP3 decoder
 * Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
 * June 2003
 *
 * assembly.h - assembly language functions and prototypes for supported platforms
 *
 * - inline rountines with access to 64-bit multiply results 
 * - x86 (_WIN32) and ARM (ARM_ADS, _WIN32_WCE) versions included
 * - some inline functions are mix of asm and C for speed
 * - some functions are in native asm files, so only the prototype is given here
 *
 * MULSHIFT32(x, y)    signed multiply of two 32-bit integers (x and y), returns top 32 bits of 64-bit result
 * FASTABS(x)          branchless absolute value of signed integer x
 * CLZ(x)              count leading zeros in x
 * MADD64(sum, x, y)   (Windows only) sum [64-bit] += x [32-bit] * y [32-bit]
 * SHL64(sum, x, y)    (Windows only) 64-bit left shift using __int64
 * SAR64(sum, x, y)    (Windows only) 64-bit right shift using __int64
 */
 
#ifndef _ASSEMBLY_H
#define _ASSEMBLY_H
 
#include <Library/BaseLib.h>
 
static __inline int MULSHIFT32(int x, int y)  
{
  return (INT32) (RShiftU64 (MultS64x64 (x, y), 32));
}
 
static __inline int FASTABS(int x) 
{
  int sign;
 
  sign = x >> (sizeof(int) * 8 - 1);
  x ^= sign;
  x -= sign;
 
  return x;
}
 
static __inline int CLZ(int x)
{
  int numZeros;
 
  if (!x)
    return (sizeof(int) * 8);
 
  numZeros = 0;
  while (!(x & 0x80000000)) {
    numZeros++;
    x <<= 1;
  } 
 
  return numZeros;
}
 
typedef INT64 Word64;
 
static __inline Word64 MADD64(Word64 sum, int x, int y)
{
  sum += MultS64x64 (x, y);
  return sum;
}
 
static __inline Word64 SHL64(Word64 x, int n)
{
  return (Word64)LShiftU64 (x, n);
}
 
static __inline Word64 SAR64(Word64 x, int n)
{
  return (Word64)RShiftU64 (x, n);
}
 
#endif /* _ASSEMBLY_H */