ia64/xen-unstable

view xen/include/asm-x86/rwlock.h @ 5193:94a63704b6c4

bitkeeper revision 1.1584 (42984f31pkIsDJAxZBlaJgFWP9L2QA)

Assembly code cleanups. gcc doesn't need very many hints to get the
operand size and register names correct for both x86/32 and x86/64.
Signed-off-by: Keir Fraser <keir@xensource.com>
author kaf24@firebug.cl.cam.ac.uk
date Sat May 28 11:00:01 2005 +0000 (2005-05-28)
parents 92b8e1efa784
children 7989e3999e83
line source
1 /* include/asm-x86/rwlock.h
2 *
3 * Helpers used by both rw spinlocks and rw semaphores.
4 *
5 * Based in part on code from semaphore.h and
6 * spinlock.h Copyright 1996 Linus Torvalds.
7 *
8 * Copyright 1999 Red Hat, Inc.
9 *
10 * Written by Benjamin LaHaise.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 */
17 #ifndef _ASM_X86_RWLOCK_H
18 #define _ASM_X86_RWLOCK_H
20 #define RW_LOCK_BIAS 0x01000000
21 #define RW_LOCK_BIAS_STR "0x01000000"
23 #define __build_read_lock_ptr(rw, helper) \
24 asm volatile(LOCK "subl $1,(%0)\n\t" \
25 "js 2f\n" \
26 "1:\n" \
27 ".section .text.lock,\"ax\"\n" \
28 "2:\tcall " helper "\n\t" \
29 "jmp 1b\n" \
30 ".previous" \
31 ::"a" (rw) : "memory")
33 #define __build_read_lock_const(rw, helper) \
34 asm volatile(LOCK "subl $1,%0\n\t" \
35 "js 2f\n" \
36 "1:\n" \
37 ".section .text.lock,\"ax\"\n" \
38 "2:\tpush %%"__OP"ax\n\t" \
39 "lea %0,%%"__OP"ax\n\t" \
40 "call " helper "\n\t" \
41 "pop %%"__OP"ax\n\t" \
42 "jmp 1b\n" \
43 ".previous" \
44 :"=m" (*(volatile int *)rw) : : "memory")
46 #define __build_read_lock(rw, helper) do { \
47 if (__builtin_constant_p(rw)) \
48 __build_read_lock_const(rw, helper); \
49 else \
50 __build_read_lock_ptr(rw, helper); \
51 } while (0)
53 #define __build_write_lock_ptr(rw, helper) \
54 asm volatile(LOCK "subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
55 "jnz 2f\n" \
56 "1:\n" \
57 ".section .text.lock,\"ax\"\n" \
58 "2:\tcall " helper "\n\t" \
59 "jmp 1b\n" \
60 ".previous" \
61 ::"a" (rw) : "memory")
63 #define __build_write_lock_const(rw, helper) \
64 asm volatile(LOCK "subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
65 "jnz 2f\n" \
66 "1:\n" \
67 ".section .text.lock,\"ax\"\n" \
68 "2:\tpush %%"__OP"ax\n\t" \
69 "lea %0,%%"__OP"ax\n\t" \
70 "call " helper "\n\t" \
71 "pop %%"__OP"ax\n\t" \
72 "jmp 1b\n" \
73 ".previous" \
74 :"=m" (*(volatile int *)rw) : : "memory")
76 #define __build_write_lock(rw, helper) do { \
77 if (__builtin_constant_p(rw)) \
78 __build_write_lock_const(rw, helper); \
79 else \
80 __build_write_lock_ptr(rw, helper); \
81 } while (0)
83 #endif