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/arch/x86/lib/cmpxchg8b_emu.S

https://bitbucket.org/thekraven/iscream_thunderc-2.6.35
Assembly | 57 lines | 52 code | 5 blank | 0 comment | 0 complexity | 2cf73f8a36667ae33f76b41455c81ebb MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
 1/*
 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)