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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 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
#if ( defined(WIN32) || defined(_WIN32) ) && !defined(WIN4)
//
// Compile for Daytona - use __int64 support on C9.
//
INLINE LONG MulDiv32( LONG a, LONG b, LONG c ) { return (LONG)( ((LONGLONG)a*b) / c ); }
INLINE DWORD MulDivRD( DWORD a, DWORD b, DWORD c ) { return (DWORD)( ((DWORDLONG)a*b) / c ); }
INLINE DWORD MulDivRN( DWORD a, DWORD b, DWORD c ) { return (DWORD)( (((DWORDLONG)a*b)+c/2) / c ); }
INLINE DWORD MulDivRU( DWORD a, DWORD b, DWORD c ) { return (DWORD)( (((DWORDLONG)a*b)+c-1) / c ); }
#else
//
// Compile for Win16 or Chicago - either way, we can use X86 assembly.
//
#pragma warning(disable:4035 4704)
#ifdef WIN32
//
// Compile for 32-bit Chicago - we can use i386 assembly.
//
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()
#else
//
// Compile for 16-bit - we can use x86 with proper opcode prefixes
// to get 32-bit instructions.
//
INLINE LONG MulDiv32(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
} // MulDiv32()
INLINE DWORD MulDivRN(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
} // MulDiv32()
INLINE DWORD MulDivRU(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
} // MulDivRU32()
INLINE DWORD MulDivRD(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
} // MulDivRD32()
#endif
#pragma warning(default:4035 4704)
#endif
//
// some code references these by other names.
//
#define muldiv32 MulDivRN
#define muldivrd32 MulDivRD
#define muldivru32 MulDivRU
#endif // _INC_MULDIV32
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