1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
;---------------------------------------------------------------------------
;/*++
;
;Copyright (c) 2006, 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:
;
; DivU64x32.c
;
;Abstract:
;
; 64-bit division function for IA-32
;
;--*/
;---------------------------------------------------------------------------
.386
.model flat,C
.code
;---------------------------------------------------------------------------
;UINT64
;DivU64x32 (
; IN UINT64 Dividend,
; IN UINTN Divisor,
; OUT UINTN *Remainder OPTIONAL
; )
;/*++
;Routine Description:
; This routine allows a 64 bit value to be divided with a 32 bit value returns
; 64bit result and the Remainder.
;
;Arguments:
; Dividend - dividend
; Divisor - divisor
; Remainder - buffer for remainder
;
;Returns:
; Dividend / Divisor
; Remainder = Dividend mod Divisor
;
;N.B. only works for 31bit divisors!!
;
;--*/
;---------------------------------------------------------------------------
DivU64x32 PROC
xor edx, edx ; Clear EDX
mov eax, [esp + 8] ; Put high 32 bits of 64-bit dividend in EAX
mov ecx, [esp + 12] ; Put 32 bits divisor in ECX
div ecx ; Dividend Divisor Quoitent...Remainder
; 0:EAX / ECX = EAX EDX
push eax ; Push quoitent in stack
mov eax, [esp + 4] ; Put low 32 bits of 64-bit dividend in EAX
div ecx ; Leave the REMAINDER in EDX as High 32-bit of new dividend
; Dividend Divisor Quoitent...Remainder
; EDX:EAX / ECX = EAX EDX
mov ecx, [esp + 16] ; Put &REMAINDER to ecx
jecxz Label1 ; If ecx == 0, no remainder exist, return with quoitent in EDX directly
mov dword ptr [ecx], edx ; Put EDX through REMAINDER pointer in ECX
Label1:
pop edx ; Pop High 32-bit QUOITENT to EDX
DivU64x32 ENDP
END
|
