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b962b6b5 | 1 | #--------------------------------------------------------------------------- |
2 | #/*++ | |
3 | # | |
4 | #Copyright (c) 2006, Intel Corporation | |
5 | #All rights reserved. This program and the accompanying materials | |
6 | #are licensed and made available under the terms and conditions of the BSD License | |
7 | #which accompanies this distribution. The full text of the license may be found at | |
8 | #http://opensource.org/licenses/bsd-license.php | |
9 | # | |
10 | #THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, | |
11 | #WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. | |
12 | # | |
13 | #Module Name: | |
14 | # | |
15 | # DivU64x32.c | |
16 | # | |
17 | #Abstract: | |
18 | # | |
19 | # 64-bit division function for IA-32 | |
20 | # | |
21 | #--*/ | |
22 | ||
23 | #--------------------------------------------------------------------------- | |
24 | #include "EfiBind.h" //For ASM_PFX | |
25 | #--------------------------------------------------------------------------- | |
26 | ||
27 | #--------------------------------------------------------------------------- | |
28 | .386: | |
29 | .code: | |
30 | ||
31 | #--------------------------------------------------------------------------- | |
32 | ||
33 | .globl ASM_PFX(DivU64x32) | |
34 | ||
35 | #UINT64 | |
36 | #DivU64x32 ( | |
37 | # IN UINT64 Dividend, | |
38 | # IN UINTN Divisor, | |
39 | # OUT UINTN *Remainder OPTIONAL | |
40 | # ) | |
41 | #/*++ | |
42 | ||
43 | #Routine Description: | |
44 | ||
45 | # This routine allows a 64 bit value to be divided with a 32 bit value returns | |
46 | # 64bit result and the Remainder. | |
47 | # | |
48 | #Arguments: | |
49 | ||
50 | # Dividend - dividend | |
51 | # Divisor - divisor | |
52 | # Remainder - buffer for remainder | |
53 | # | |
54 | #Returns: | |
55 | ||
56 | # Dividend / Divisor | |
57 | # Remainder = Dividend mod Divisor | |
58 | # | |
59 | #N.B. only works for 31bit divisors!! | |
60 | # | |
61 | #--*/ | |
62 | #--------------------------------------------------------------------------- | |
63 | ||
64 | ASM_PFX(DivU64x32): | |
65 | pushl %ebp | |
66 | movl %esp, %ebp | |
67 | xorl %edx, %edx # Clear EDX | |
68 | ||
69 | movl 0xC(%ebp), %eax # Put high 32 bits of 64-bit dividend in EAX | |
70 | movl 0x10(%ebp), %ecx # Put 32 bits divisor in ECX | |
71 | divl %ecx # Dividend Divisor Quoitent...Remainder | |
72 | # 0:EAX / ECX = EAX EDX | |
73 | ||
74 | pushl %eax # Push quoitent in stack | |
75 | ||
76 | movl 8(%ebp), %eax # Put low 32 bits of 64-bit dividend in EAX | |
77 | divl %ecx # Leave the REMAINDER in EDX as High 32-bit of new dividend | |
78 | # Dividend Divisor Quoitent...Remainder | |
79 | # EDX:EAX / ECX = EAX EDX | |
80 | ||
81 | movl 0x14(%ebp), %ecx # Put &REMAINDER to ecx | |
82 | ||
83 | jecxz Label1 # If ecx == 0, no remainder exist, return with quoitent in EDX directly | |
84 | movl %edx, (%ecx) # Put EDX through REMAINDER pointer in ECX | |
85 | ||
86 | Label1: | |
87 | popl %edx # Pop High 32-bit QUOITENT to EDX | |
88 | popl %ebp | |
89 | ||
90 | ret | |
91 |