mp3assembly.h

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/* ***** BEGIN LICENSE BLOCK ***** 
 * Version: RCSL 1.0/RPSL 1.0 
 *  
 * Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved. 
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 * the file under the RealNetworks Community Source License Version 1.0 
 * (the "RCSL") available at http://www.helixcommunity.org/content/rcsl, 
 * in which case the RCSL will apply. You may also obtain the license terms 
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 * applicable to this file, the RCSL.  Please see the applicable RPSL or 
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 * This file is part of the Helix DNA Technology. RealNetworks is the 
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 * ***** END LICENSE BLOCK ***** */ 

/**************************************************************************************
 * Fixed-point MP3 decoder
 * Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
 * June 2003
 *
 * mp3assembly.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 "mp3dec.h"

/* toolchain:           ARM gcc
 * target architecture: ARM v7-m 
 */
#if defined(__GNUC__) && (defined(ARM) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7EM__))

typedef long long Word64;

typedef union _U64 
{
    Word64 w64;
    struct 
    {
        unsigned int lo32;
        signed int   hi32;
    }r;
} U64;

#define MULSHIFT32  xmp3_MULSHIFT32
extern  int MULSHIFT32(int x, int y);

#define FASTABS xmp3_FASTABS
extern  int FASTABS(int x);

static inline Word64 MADD64(Word64 sum64, int x, int y)
{
    U64 u;
    u.w64 = sum64;
    __asm__ volatile ("smlal %0,%1,%2,%3" : "+&r" (u.r.lo32), "+&r" (u.r.hi32) : "r" (x), "r" (y) : "cc");
    return u.w64;
}

static inline long long SAR64(long long x, int n)
{
    long long ret = x;
    ret = ret>>n;
    return ret;
}

#define CLZ(x)       __CLZ(x)

#define CLIPTO30(x)  __SSAT(x,30)


/* toolchain:           iar iccarm
 * target architecture: ARM v7-m 
 */
#elif defined(__ICCARM__)

typedef long long Word64;

#define MULSHIFT32  xmp3_MULSHIFT32
extern  int MULSHIFT32(int x, int y);

#define FASTABS xmp3_FASTABS
extern  int FASTABS(int x);

static inline long long MADD64(long long sum, int x, int y)
{
    return (sum +(long long)x * y);
}

static inline long long SAR64(long long x, int n)
{
    long long ret = x;
    ret = ret>>n;
    return ret;
}

#define CLZ(x)       __CLZ(x)

#define CLIPTO30(x)  __SSAT(x,30)

#else

typedef long long Word64;

_XIF_ static inline int MULSHIFT32(int x, int y)
{
    int z;
    z = (Word64)x * (Word64)y >> 32;
    return z;
}

_XIF_ static inline  int FASTABS(int x)
{
    int sign;
    sign = x >> (sizeof(int) * 8 -1);
    x ^= sign;
    x -= sign;
    return x;
}

_XIF_ static inline long long MADD64(long long sum, int x, int y)
{
    return (sum +(long long)x * y);
}

_XIF_ static inline long long SAR64(long long x, int n)
{
    long long ret = x;
    ret = ret>>n;
    return ret;
}

_XIF_ static inline int CLZ(int x)
{
    int numZeros;

    if(!x)
        return 32;

    numZeros = 1;
    if(!((unsigned int)x >> 16)) { numZeros += 16; x <<= 16;}
    if(!((unsigned int)x >> 24)) { numZeros += 8; x <<= 8;}
    if(!((unsigned int)x >> 28)) { numZeros += 4; x <<= 4;}
    if(!((unsigned int)x >> 30)) { numZeros += 2; x <<= 2;}

    numZeros -= ((unsigned int)x >> 31);

    return numZeros;
}

_XIF_ static inline int CLIPTO30(int x)
{
    int sign;

    sign = x>>31;
    if(sign != (x >> 30))
        x = sign ^ ((1 << 30)-1);

    return x;
}

#endif  /* platforms */

#endif /* _ASSEMBLY_H */