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; Copyright (c) 2004, Intel Corporation
; All rights reserved. This program and the accompanying materials
; are licensed and made available under the terms and conditions of the BSD License
; which accompanies this distribution. The full text of the license may be found at
; http://opensource.org/licenses/bsd-license.php
;
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;
; Module Name:
;
; DivU64x64Remainder.asm
;
; Abstract:
;
; Calculate the quotient of a 64-bit integer by a 64-bit integer and returns
; both the quotient and the remainder
;
;------------------------------------------------------------------------------
.386
.model flat,C
.code
EXTERN InternalMathDivRemU64x32:PROC
;------------------------------------------------------------------------------
; UINT64
; EFIAPI
; InternalMathDivRemU64x64 (
; IN UINT64 Dividend,
; IN UINT64 Divisor,
; OUT UINT64 *Remainder OPTIONAL
; );
;------------------------------------------------------------------------------
InternalMathDivRemU64x64 PROC
mov ecx, [esp + 16]
test ecx, ecx
jnz _@DivRemU64x64 ; call _@DivRemU64x64 if Divisor > 2^32
mov ecx, [esp + 20]
jecxz @F
and dword ptr [ecx + 4], 0
mov [esp + 16], ecx
@@:
jmp InternalMathDivRemU64x32
InternalMathDivRemU64x64 ENDP
_@DivRemU64x64 PROC USES ebx esi edi
mov edx, dword ptr [esp + 20]
mov eax, dword ptr [esp + 16] ; edx:eax <- dividend
mov edi, edx
mov esi, eax ; edi:esi <- dividend
mov ebx, dword ptr [esp + 24] ; ecx:ebx <- divisor
@@:
shr edx, 1
rcr eax, 1
shrd ebx, ecx, 1
shr ecx, 1
jnz @B
div ebx
mov ebx, eax ; ebx <- quotient
mov ecx, [esp + 28]
mul dword ptr [esp + 24]
imul ecx, ebx
add edx, ecx
mov ecx, dword ptr [esp + 32]
jc @TooLarge ; product > 2^64
cmp edi, edx ; compare high 32 bits
ja @Correct
jb @TooLarge ; product > dividend
cmp esi, eax
jae @Correct ; product <= dividend
@TooLarge:
dec ebx ; adjust quotient by -1
jecxz @Return ; return if Remainder == NULL
sub eax, dword ptr [esp + 24]
sbb edx, dword ptr [esp + 28]
@Correct:
jecxz @Return
sub esi, eax
sbb edi, edx ; edi:esi <- remainder
mov [ecx], esi
mov [ecx + 4], edi
@Return:
mov eax, ebx ; eax <- quotient
xor edx, edx
ret
_@DivRemU64x64 ENDP
END
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