2 * Copyright (C) 2005 Internet Systems Consortium, Inc. ("ISC")
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
8 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
9 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
10 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
11 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
12 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
13 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
14 * PERFORMANCE OF THIS SOFTWARE.
17 /* $Id: atomic.h,v 1.2.20.1 2005/09/02 13:27:12 marka Exp $ */
20 #define ISC_ATOMIC_H 1
22 #include <isc/platform.h>
23 #include <isc/types.h>
25 #ifdef ISC_PLATFORM_USEGCCASM
27 /* We share the gcc-version with x86_32 */
28 #error "impossible case. check build configuration"
30 #elif defined(ISC_PLATFORM_USESTDASM)
32 * The followings are "generic" assembly code which implements the same
33 * functionality in case the gcc extension cannot be used. It should be
34 * better to avoid inlining below, since we directly refer to specific
35 * registers for arguments, which would not actually correspond to the
36 * intended address or value in the embedded mnemonic.
38 #include <isc/util.h> /* for 'UNUSED' macro */
41 isc_atomic_xadd(isc_int32_t *p, isc_int32_t val) {
48 #ifdef ISC_PLATFORM_USETHREADS
54 * set the return value directly in the register so that we
55 * can avoid guessing the correct position in the stack for a
62 isc_atomic_store(isc_int32_t *p, isc_int32_t val) {
69 #ifdef ISC_PLATFORM_USETHREADS
72 "xchgl (%rax), %edx\n"
77 isc_atomic_cmpxchg(isc_int32_t *p, isc_int32_t cmpval, isc_int32_t val) {
87 #ifdef ISC_PLATFORM_USETHREADS
91 * If (%rdi) == %eax then (%rdi) := %edx.
92 % %eax is set to old (%ecx), which will be the return value.
94 "cmpxchgl %ecx, (%rdx)"
98 #else /* !ISC_PLATFORM_USEGCCASM && !ISC_PLATFORM_USESTDASM */
100 #error "unsupported compiler. disable atomic ops by --disable-atomic"
103 #endif /* ISC_ATOMIC_H */