MULDIV32.H

//==========================================================================; 
// 
//  THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY 
//  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
//  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR 
//  PURPOSE. 
// 
//  Copyright 1992 - 1998 Microsoft Corporation.  All Rights Reserved. 
// 
//--------------------------------------------------------------------------; 
// 
//  muldiv32.h 
// 
//  Description: 
//      math routines for 32 bit signed and unsiged numbers. 
// 
//      MulDiv32(a,b,c) = (a * b) / c         (round down, signed) 
// 
//      MulDivRD(a,b,c) = (a * b) / c         (round down, unsigned) 
//      MulDivRN(a,b,c) = (a * b + c/2) / c   (round nearest, unsigned) 
//      MulDivRU(a,b,c) = (a * b + c-1) / c   (round up, unsigned) 
// 
//==========================================================================; 
 
#ifndef _INC_MULDIV32 
#define _INC_MULDIV32 
 
 
#ifndef INLINE 
#define INLINE __inline 
#endif 
 
 
#ifdef _X86_ 
 
    // 
    //  Use 32-bit x86 assembly. 
    // 
 
    #pragma warning(disable:4035 4704) 
 
    INLINE LONG MulDiv32(LONG a,LONG b,LONG c) 
    { 
        _asm     mov     eax,dword ptr a  //  mov  eax, a 
        _asm     mov     ebx,dword ptr b  //  mov  ebx, b 
        _asm     mov     ecx,dword ptr c  //  mov  ecx, c 
        _asm     imul    ebx              //  imul ebx 
        _asm     idiv    ecx              //  idiv ecx 
        _asm shld edx, eax, 16     //  shld edx, eax, 16 
 
    } // MulDiv32() 
 
    INLINE DWORD MulDivRN(DWORD a,DWORD b,DWORD c) 
    { 
        _asm     mov     eax,dword ptr a  //  mov  eax, a 
        _asm     mov     ebx,dword ptr b  //  mov  ebx, b 
        _asm     mov     ecx,dword ptr c  //  mov  ecx, c 
        _asm     mul     ebx              //  mul  ebx 
        _asm     mov     ebx,ecx          //  mov  ebx,ecx 
        _asm     shr     ebx,1            //  sar  ebx,1 
        _asm     add     eax,ebx          //  add  eax,ebx 
        _asm     adc     edx,0            //  adc  edx,0 
        _asm     div     ecx              //  div  ecx 
        _asm     shld    edx, eax, 16     //  shld edx, eax, 16 
 
    } // MulDiv32() 
 
    INLINE DWORD MulDivRU(DWORD a,DWORD b,DWORD c) 
    { 
        _asm     mov     eax,dword ptr a  //  mov  eax, a 
        _asm     mov     ebx,dword ptr b  //  mov  ebx, b 
        _asm     mov     ecx,dword ptr c  //  mov  ecx, c 
        _asm     mul     ebx              //  mul  ebx 
        _asm     mov     ebx,ecx          //  mov  ebx,ecx 
        _asm     dec     ebx              //  dec  ebx 
        _asm     add     eax,ebx          //  add  eax,ebx 
        _asm     adc     edx,0            //  adc  edx,0 
        _asm     div     ecx              //  div  ecx 
        _asm     shld    edx, eax, 16     //  shld edx, eax, 16 
 
    } // MulDivRU32() 
 
    INLINE DWORD MulDivRD(DWORD a,DWORD b,DWORD c) 
    { 
        _asm     mov     eax,dword ptr a  //  mov  eax, a 
        _asm     mov     ebx,dword ptr b  //  mov  ebx, b 
        _asm     mov     ecx,dword ptr c  //  mov  ecx, c 
        _asm     mul     ebx              //  mul  ebx 
        _asm     div     ecx              //  div  ecx 
        _asm     shld    edx, eax, 16     //  shld edx, eax, 16 
 
    } // MulDivRD32() 
 
    #pragma warning(default:4035 4704) 
 
 
#else 
 
    // 
    //  Use C9 __int64 support for Daytona RISC platforms. 
    // 
 
    INLINE LONG MulDiv32( LONG a, LONG b, LONG c ) 
    { 
        return (LONG)( Int32x32To64(a,b) / c ); 
    } 
 
 
    INLINE DWORD MulDivRD( DWORD a, DWORD b, DWORD c ) 
    { 
        return (DWORD)( UInt32x32To64(a,b) / c ); 
    } 
 
 
    INLINE DWORD MulDivRN( DWORD a, DWORD b, DWORD c ) 
    { 
        return (DWORD)( (UInt32x32To64(a,b)+c/2) / c ); 
    } 
 
 
    INLINE DWORD MulDivRU( DWORD a, DWORD b, DWORD c ) 
    { 
        return (DWORD)( (UInt32x32To64(a,b)+c-1) / c ); 
    } 
 
#endif 
 
 
// 
//  some code references these by other names. 
// 
#define muldiv32    MulDivRN 
#define muldivrd32  MulDivRD 
#define muldivru32  MulDivRU 
 
#endif  // _INC_MULDIV32