mathhelp32.h

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//==========================================================================;
//
//  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 (c) 1992-1994 G&G Lab Corporation
//
//--------------------------------------------------------------------------;
//
//  MathHelp32.h
//
//  Description:
//      math routines for 32 bit signed and unsiged numbers.
//
//      MathHelp32(a,b,c) = (a * b) / c         (round down, signed)
//
//      MathHelpRD(a,b,c) = (a * b) / c         (round down, unsigned)
//      MathHelpRN(a,b,c) = (a * b + c/2) / c   (round nearest, unsigned)
//      MathHelpRU(a,b,c) = (a * b + c-1) / c   (round up, unsigned)
//
//==========================================================================;

#ifndef _INC_MATHHELP32
#define _INC_MATHHELP32


#ifndef INLINE
#define INLINE __inline
#endif


#ifdef WIN32

    //----------------------------------------------------------------------;
    //
    //  Win 32
    //
    //----------------------------------------------------------------------;

    #ifdef _X86_
    
        //
        //  Use 32-bit x86 assembly.
        //

        #pragma warning(disable:4035 4704)

        INLINE LONG MathHelp32(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

        } // MathHelp32()

        INLINE DWORD MathHelpRN(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

        } // MathHelp32()

        INLINE DWORD MathHelpRU(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

        } // MathHelpRU32()

        INLINE DWORD MathHelpRD(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

        } // MathHelpRD32()

        #pragma warning(default:4035 4704)


    #else

        //
        //  Use C9 __int64 support for Daytona RISC platforms.
        //

        INLINE LONG MathHelp32( LONG a, LONG b, LONG c )
        {
            return (LONG)( Int32x32To64(a,b) / c );
        }


        INLINE DWORD MathHelpRD( DWORD a, DWORD b, DWORD c )
        {
            return (DWORD)( UInt32x32To64(a,b) / c );
        }


        INLINE DWORD MathHelpRN( DWORD a, DWORD b, DWORD c )
        {
            return (DWORD)( (UInt32x32To64(a,b)+c/2) / c );
        }


        INLINE DWORD MathHelpRU( DWORD a, DWORD b, DWORD c )
        {
            return (DWORD)( (UInt32x32To64(a,b)+c-1) / c );
        }

    #endif


#else

    //----------------------------------------------------------------------;
    //
    //  Win 16
    //
    //----------------------------------------------------------------------;

    #pragma warning(disable:4035 4704)

    //
    //  Compile for 16-bit - we can use x86 with proper opcode prefixes
    //	    to get 32-bit instructions.
    //

    INLINE LONG MathHelp32(LONG a,LONG b,LONG c)
    {
        _asm _emit 0x66 _asm    mov     ax,word ptr a   //  mov  eax, a
        _asm _emit 0x66 _asm    mov     bx,word ptr b   //  mov  ebx, b
        _asm _emit 0x66 _asm    mov     cx,word ptr c   //  mov  ecx, c
        _asm _emit 0x66 _asm    imul    bx              //  imul ebx
        _asm _emit 0x66 _asm    idiv    cx              //  idiv ecx
        _asm _emit 0x66                                 //  shld edx, eax, 16
        _asm _emit 0x0F
        _asm _emit 0xA4
        _asm _emit 0xC2
        _asm _emit 0x10

    } // MathHelp32()

    INLINE DWORD MathHelpRN(DWORD a,DWORD b,DWORD c)
    {
        _asm _emit 0x66 _asm    mov     ax,word ptr a   //  mov  eax, a
        _asm _emit 0x66 _asm    mov     bx,word ptr b   //  mov  ebx, b
        _asm _emit 0x66 _asm    mov     cx,word ptr c   //  mov  ecx, c
        _asm _emit 0x66 _asm    mul     bx              //  mul  ebx
        _asm _emit 0x66 _asm    mov     bx,cx           //  mov  ebx,ecx
        _asm _emit 0x66 _asm    shr     bx,1            //  sar  ebx,1
        _asm _emit 0x66 _asm    add     ax,bx           //  add  eax,ebx
        _asm _emit 0x66 _asm    adc     dx,0            //  adc  edx,0
        _asm _emit 0x66 _asm    div     cx              //  div  ecx
        _asm _emit 0x66                                 //  shld edx, eax, 16
        _asm _emit 0x0F
        _asm _emit 0xA4
        _asm _emit 0xC2
        _asm _emit 0x10

    } // MathHelp32()

    INLINE DWORD MathHelpRU(DWORD a,DWORD b,DWORD c)
    {
        _asm _emit 0x66 _asm    mov     ax,word ptr a   //  mov  eax, a
        _asm _emit 0x66 _asm    mov     bx,word ptr b   //  mov  ebx, b
        _asm _emit 0x66 _asm    mov     cx,word ptr c   //  mov  ecx, c
        _asm _emit 0x66 _asm    mul     bx              //  mul  ebx
        _asm _emit 0x66 _asm    mov     bx,cx           //  mov  ebx,ecx
        _asm _emit 0x66 _asm    dec     bx              //  dec  ebx
        _asm _emit 0x66 _asm    add     ax,bx           //  add  eax,ebx
        _asm _emit 0x66 _asm    adc     dx,0            //  adc  edx,0
        _asm _emit 0x66 _asm    div     cx              //  div  ecx
        _asm _emit 0x66                                 //  shld edx, eax, 16
        _asm _emit 0x0F
        _asm _emit 0xA4
        _asm _emit 0xC2
        _asm _emit 0x10

    } // MathHelpRU32()


    INLINE DWORD MathHelpRD(DWORD a,DWORD b,DWORD c)
    {
        _asm _emit 0x66 _asm    mov     ax,word ptr a   //  mov  eax, a
        _asm _emit 0x66 _asm    mov     bx,word ptr b   //  mov  ebx, b
        _asm _emit 0x66 _asm    mov     cx,word ptr c   //  mov  ecx, c
        _asm _emit 0x66 _asm    mul     bx              //  mul  ebx
        _asm _emit 0x66 _asm    div     cx              //  div  ecx
        _asm _emit 0x66                                 //  shld edx, eax, 16
        _asm _emit 0x0F
        _asm _emit 0xA4
        _asm _emit 0xC2
        _asm _emit 0x10

    } // MathHelpRD32()

    #pragma warning(default:4035 4704)

#endif


//
//  some code references these by other names.
//
#define MathHelp32    MathHelpRN
#define MathHelprd32  MathHelpRD
#define MathHelpru32  MathHelpRU

#endif  // _INC_MATHHELP32