blob: 828cb710dec29c38a1c0d588108accabf7562c0a [file] [log] [blame]
Arjan van de Ven79e1dd02009-09-30 17:07:54 +02001/*
2 * This program is free software; you can redistribute it and/or
3 * modify it under the terms of the GNU General Public License
4 * as published by the Free Software Foundation; version 2
5 * of the License.
6 *
7 */
8
9#include <linux/linkage.h>
10#include <asm/alternative-asm.h>
11#include <asm/frame.h>
12#include <asm/dwarf2.h>
13
14
15.text
16
17/*
18 * Inputs:
19 * %esi : memory location to compare
20 * %eax : low 32 bits of old value
21 * %edx : high 32 bits of old value
22 * %ebx : low 32 bits of new value
23 * %ecx : high 32 bits of new value
24 */
25ENTRY(cmpxchg8b_emu)
26CFI_STARTPROC
27
28#
29# Emulate 'cmpxchg8b (%esi)' on UP except we don't
30# set the whole ZF thing (caller will just compare
31# eax:edx with the expected value)
32#
33cmpxchg8b_emu:
34 pushfl
35 cli
36
37 cmpl (%esi), %eax
38 jne not_same
39 cmpl 4(%esi), %edx
40 jne half_same
41
42 movl %ebx, (%esi)
43 movl %ecx, 4(%esi)
44
45 popfl
46 ret
47
48 not_same:
49 movl (%esi), %eax
50 half_same:
51 movl 4(%esi), %edx
52
53 popfl
54 ret
55
56CFI_ENDPROC
57ENDPROC(cmpxchg8b_emu)