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
|
/*++
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
--*/
#include "Tiano.h"
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!!
--*/
{
__asm {
xor edx, edx ; Clear EDX
mov eax, dword ptr Dividend[4] ; Put high 32 bits of 64-bit dividend in EAX
mov ecx, Divisor ; 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, dword ptr Dividend[0] ; 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, Remainder ; 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
}
}
|
