UT/UT_CommonMMXFuncs.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * Authored by:
 *      Mark Alexander
 *      Side Effects Software Inc.
 *
 * NAME:        UT_CommonMMXFuncs.h (Utility Library, C++)
 *
 * COMMENTS:
 *      Common MMX functions. They do not check for whether MMX/SSE are
 *      actually present - it is up to the programmer to check beforehand.
 */

#ifndef __UT_CommonMMXFuncs_h__
#define __UT_CommonMMXFuncs_h__

#include "UT_API.h"
#include <SYS/SYS_Types.h>
#include "UT_Floor.h"

#ifdef LINUX
#if !defined(IA64) && !defined(AMD64) && !defined(PPC)
#define UT_USE_ASM_ACCEL
#endif
#endif

// You must ensure that the processor supports SSE before calling these
// functions by calling UTgetProcessor() and checking for UT_PROCFLAG_SSE or
// UT_PROCFLAG_3DNOW. This is not done in these functions as it would be
// pretty inefficent.

// The FP -> int versions are much faster because clamping does not have
// any branches (about 10x). The int->FP versions are slightly faster (1.5x).
// Performance tested on Linux RH7, P4.

// Float to byte conversions; (0-1) -> (0-255) and (0,1) -> (b,w)
UT_API void UTconvertFPto8(unsigned char        *dest,
                           const fpreal32       *source,
                           int                   length,
                           int                   useprocext = 0);

UT_API void UTconvertFPto8BW(unsigned char      *dest,
                             const fpreal32     *source,
                             int                 length,
                             unsigned int        black,
                             unsigned int        white,
                             int                 useprocext = 0);

// byte to fpreal32 conversions; (0-65535) -> (0-1) and (b,w) -> (0,1)
UT_API void UTconvert8toFP(fpreal32             *dest,
                           const unsigned char  *source,
                           int                   length,
                           bool                  usesse = true);

UT_API void UTconvert8BWtoFP(fpreal32           *dest,
                             const unsigned char*source,
                             int                 length,
                             unsigned int        black,
                             unsigned int        white,
                             bool                usesse = true);

// Float to short conversions; (0-1) -> (0-65535) and (0,1) -> (b,w)
UT_API void UTconvertFPto16(unsigned short      *dest,
                            const fpreal32      *source,
                            int                  length,
                            int                  procext = 0);

UT_API void UTconvertFPto16BW(unsigned short    *dest,
                              const fpreal32    *source,
                              int                length,
                              unsigned int       black,
                              unsigned int       white,
                              bool               usesse = true);

// short to fpreal32 conversions; (0-65535) -> (0-1) and (b,w) -> (0,1)
UT_API void UTconvert16toFP(fpreal32            *dest,
                            const unsigned short*source,
                            int                  length,
                            bool                 usesse = true);

UT_API void UTconvert16BWtoFP(fpreal32          *dest,
                              const unsigned short *source,
                              int                length,
                              unsigned int       black,
                              unsigned int       white,
                              bool               usesse = true);

// The next 2 functions convert FP numbers to 8 bit and 16 bit values.
UT_API inline unsigned char UTconvertFPto8(fpreal32 fval)
{
    unsigned char val;
    
#ifdef UT_USE_ASM_ACCEL
    const fpreal32 f255[1] = { 255.0f };
    const fpreal32 *fptr = &fval;
    int ival = 0;

    __asm__ __volatile (
        "movss  (%%edi), %%xmm0         \n"
        "movss  (%%ebx), %%xmm1         \n"
        "mov    $255, %%ecx             \n" // ecx = 255
        "mulss  %%xmm1, %%xmm0          \n"
        "mov    $0,   %%ebx             \n" // ebx = 0
        "cvtss2si       %%xmm0, %%eax           \n"
        "cmp    %%eax,  %%ecx           \n" // compare to 255
        "cmovl  %%ecx,  %%eax           \n"
        "cmp    %%eax, %%ebx            \n" // compare to 0
        "cmovg  %%ebx, %%eax            \n"
        : "=a" (ival)
        : "D" (fptr),
          "b" (f255) : "%ecx");

    val = (unsigned char) ival;
#else
    int t = (int) UTfloorIL(fval * 255.0f +0.5F);
    
    if(t < 0)
        val = 0;
    else if(t > 255)
        val = 255;
    else
        val = (unsigned char) t;
#endif    
    return val;
}

UT_API inline unsigned short UTconvertFPto16(fpreal32 fval)
{
    unsigned short val;
    
#ifdef UT_USE_ASM_ACCEL
    const fpreal32 f65535[1] = { 65535.0f };
    const fpreal32 *fptr = &fval;
    int ival = 0;
        
    __asm__ __volatile (
        "movss  (%%edi), %%xmm0         \n"
        "movss  (%%ebx), %%xmm1         \n"
        "mov    $65535, %%ecx           \n" // ecx = 65535
        "mulss  %%xmm1, %%xmm0          \n"
        "mov    $0,   %%ebx             \n" // ebx = 0
        "cvtss2si       %%xmm0, %%eax           \n"
        "cmp    %%eax,  %%ecx           \n" // compare to 65535
        "cmovl  %%ecx,  %%eax           \n"
        "cmp    %%eax, %%ebx            \n" // compare to 0
        "cmovg  %%ebx, %%eax            \n"
        : "=a" (ival)
        : "D" (fptr),
          "b" (f65535) : "%ecx");
    
    val = (unsigned short) ival;
#else
    int t = (int) UTfloorIL(fval * 65535.0f +0.5F);
    if(t < 0)
        val = 0;
    else if(t > 65535)
        val = 65535;
    else
        val = (unsigned short) t;
#endif
    return val;
}

#endif

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