220 lines
7.2 KiB
C
220 lines
7.2 KiB
C
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//==========================================================================;
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//
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// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
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// KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
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// PURPOSE.
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//
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// Copyright (c) 1992 - 1994 Microsoft Corporation. All Rights Reserved.
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//
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//--------------------------------------------------------------------------;
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//
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// muldiv32.h
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//
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// Description:
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// math routines for 32 bit signed and unsiged numbers.
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//
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// MulDiv32(a,b,c) = (a * b) / c (round down, signed)
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//
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// MulDivRD(a,b,c) = (a * b) / c (round down, unsigned)
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// MulDivRN(a,b,c) = (a * b + c/2) / c (round nearest, unsigned)
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// MulDivRU(a,b,c) = (a * b + c-1) / c (round up, unsigned)
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//
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//==========================================================================;
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#ifndef _INC_MULDIV32
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#define _INC_MULDIV32
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#ifndef INLINE
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#define INLINE __inline
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#endif
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#if ( defined(WIN32) || defined(_WIN32) ) && !defined(WIN4)
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//
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// Compile for Daytona - use __int64 support on C9.
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//
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INLINE LONG MulDiv32( LONG a, LONG b, LONG c )
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{
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return (LONG)( ((LONGLONG)a*b) / c );
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}
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INLINE DWORD MulDivRD( DWORD a, DWORD b, DWORD c )
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{
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return (DWORD)( ((DWORDLONG)a*b) / c );
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}
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INLINE DWORD MulDivRN( DWORD a, DWORD b, DWORD c )
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{
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return (DWORD)( (((DWORDLONG)a*b)+c/2) / c );
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}
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INLINE DWORD MulDivRU( DWORD a, DWORD b, DWORD c )
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{
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return (DWORD)( (((DWORDLONG)a*b)+c-1) / c );
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}
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#else
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//
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// Compile for Win16 or Chicago - either way, we can use X86 assembly.
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//
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#pragma warning(disable:4035 4704)
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#ifdef WIN32
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//
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// Compile for 32-bit Chicago - we can use i386 assembly.
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//
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INLINE LONG MulDiv32(LONG a,LONG b,LONG c)
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{
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_asm mov eax,dword ptr a // mov eax, a
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_asm mov ebx,dword ptr b // mov ebx, b
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_asm mov ecx,dword ptr c // mov ecx, c
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_asm imul ebx // imul ebx
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_asm idiv ecx // idiv ecx
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_asm shld edx, eax, 16 // shld edx, eax, 16
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} // MulDiv32()
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INLINE DWORD MulDivRN(DWORD a,DWORD b,DWORD c)
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{
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_asm mov eax,dword ptr a // mov eax, a
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_asm mov ebx,dword ptr b // mov ebx, b
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_asm mov ecx,dword ptr c // mov ecx, c
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_asm mul ebx // mul ebx
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_asm mov ebx,ecx // mov ebx,ecx
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_asm shr ebx,1 // sar ebx,1
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_asm add eax,ebx // add eax,ebx
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_asm adc edx,0 // adc edx,0
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_asm div ecx // div ecx
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_asm shld edx, eax, 16 // shld edx, eax, 16
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} // MulDiv32()
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INLINE DWORD MulDivRU(DWORD a,DWORD b,DWORD c)
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{
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_asm mov eax,dword ptr a // mov eax, a
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_asm mov ebx,dword ptr b // mov ebx, b
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_asm mov ecx,dword ptr c // mov ecx, c
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_asm mul ebx // mul ebx
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_asm mov ebx,ecx // mov ebx,ecx
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_asm dec ebx // dec ebx
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_asm add eax,ebx // add eax,ebx
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_asm adc edx,0 // adc edx,0
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_asm div ecx // div ecx
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_asm shld edx, eax, 16 // shld edx, eax, 16
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} // MulDivRU32()
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INLINE DWORD MulDivRD(DWORD a,DWORD b,DWORD c)
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{
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_asm mov eax,dword ptr a // mov eax, a
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_asm mov ebx,dword ptr b // mov ebx, b
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_asm mov ecx,dword ptr c // mov ecx, c
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_asm mul ebx // mul ebx
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_asm div ecx // div ecx
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_asm shld edx, eax, 16 // shld edx, eax, 16
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} // MulDivRD32()
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#else
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//
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// Compile for 16-bit - we can use x86 with proper opcode prefixes
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// to get 32-bit instructions.
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//
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INLINE LONG MulDiv32(LONG a,LONG b,LONG c)
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{
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_asm _emit 0x66 _asm mov ax,word ptr a // mov eax, a
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_asm _emit 0x66 _asm mov bx,word ptr b // mov ebx, b
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_asm _emit 0x66 _asm mov cx,word ptr c // mov ecx, c
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_asm _emit 0x66 _asm imul bx // imul ebx
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_asm _emit 0x66 _asm idiv cx // idiv ecx
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_asm _emit 0x66 // shld edx, eax, 16
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_asm _emit 0x0F
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_asm _emit 0xA4
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_asm _emit 0xC2
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_asm _emit 0x10
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} // MulDiv32()
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INLINE DWORD MulDivRN(DWORD a,DWORD b,DWORD c)
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{
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_asm _emit 0x66 _asm mov ax,word ptr a // mov eax, a
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_asm _emit 0x66 _asm mov bx,word ptr b // mov ebx, b
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_asm _emit 0x66 _asm mov cx,word ptr c // mov ecx, c
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_asm _emit 0x66 _asm mul bx // mul ebx
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_asm _emit 0x66 _asm mov bx,cx // mov ebx,ecx
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_asm _emit 0x66 _asm shr bx,1 // sar ebx,1
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_asm _emit 0x66 _asm add ax,bx // add eax,ebx
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_asm _emit 0x66 _asm adc dx,0 // adc edx,0
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_asm _emit 0x66 _asm div cx // div ecx
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_asm _emit 0x66 // shld edx, eax, 16
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_asm _emit 0x0F
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_asm _emit 0xA4
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_asm _emit 0xC2
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_asm _emit 0x10
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} // MulDiv32()
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INLINE DWORD MulDivRU(DWORD a,DWORD b,DWORD c)
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{
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_asm _emit 0x66 _asm mov ax,word ptr a // mov eax, a
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_asm _emit 0x66 _asm mov bx,word ptr b // mov ebx, b
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_asm _emit 0x66 _asm mov cx,word ptr c // mov ecx, c
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_asm _emit 0x66 _asm mul bx // mul ebx
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_asm _emit 0x66 _asm mov bx,cx // mov ebx,ecx
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_asm _emit 0x66 _asm dec bx // dec ebx
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_asm _emit 0x66 _asm add ax,bx // add eax,ebx
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_asm _emit 0x66 _asm adc dx,0 // adc edx,0
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_asm _emit 0x66 _asm div cx // div ecx
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_asm _emit 0x66 // shld edx, eax, 16
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_asm _emit 0x0F
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_asm _emit 0xA4
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_asm _emit 0xC2
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_asm _emit 0x10
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} // MulDivRU32()
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INLINE DWORD MulDivRD(DWORD a,DWORD b,DWORD c)
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{
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_asm _emit 0x66 _asm mov ax,word ptr a // mov eax, a
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_asm _emit 0x66 _asm mov bx,word ptr b // mov ebx, b
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_asm _emit 0x66 _asm mov cx,word ptr c // mov ecx, c
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_asm _emit 0x66 _asm mul bx // mul ebx
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_asm _emit 0x66 _asm div cx // div ecx
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_asm _emit 0x66 // shld edx, eax, 16
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_asm _emit 0x0F
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_asm _emit 0xA4
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_asm _emit 0xC2
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_asm _emit 0x10
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} // MulDivRD32()
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#endif
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#pragma warning(default:4035 4704)
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#endif
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//
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// some code references these by other names.
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//
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#define muldiv32 MulDivRN
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#define muldivrd32 MulDivRD
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#define muldivru32 MulDivRU
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#endif // _INC_MULDIV32
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