atomic.h revision c528bd698637d84a0081d26a58813607c7f52bb7
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * Copyright (C) 2005 Internet Systems Consortium, Inc. ("ISC")
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * Permission to use, copy, modify, and distribute this software for any
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * purpose with or without fee is hereby granted, provided that the above
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * copyright notice and this permission notice appear in all copies.
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * PERFORMANCE OF THIS SOFTWARE.
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉/* $Id: atomic.h,v 1.3 2005/06/16 21:58:00 jinmei Exp $ */
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * This routine atomically increments the value stored in 'p' by 'val', and
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * returns the previous value.
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉isc_atomic_xadd(isc_int32_t *p, isc_int32_t val) {
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * This routine atomically stores the value 'val' in 'p'.
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉static inline void
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉isc_atomic_store(isc_int32_t *p, isc_int32_t val) {
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * xchg should automatically lock memory, but we add it
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * explicitly just in case (it at least doesn't harm)
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 "xchgl %1, %0"
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * This routine atomically replaces the value in 'p' with 'val', if the
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 * original value is equal to 'cmpval'. The original value is returned in any
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉isc_atomic_cmpxchg(isc_int32_t *p, isc_int32_t cmpval, isc_int32_t val) {
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉 "cmpxchgl %1, %2"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * The followings are "generic" assembly code which implements the same
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * functionality in case the gcc extension cannot be used. It should be
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * better to avoid inlining below, since we directly refer to specific
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * positions of the stack frame, which would not actually point to the
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * intended address in the embedded mnemonic.
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * XXX: this code may also not work on a 64-bit (w/o gcc) machine.
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉#include <isc/util.h> /* for 'UNUSED' macro */
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉isc_atomic_xadd(isc_int32_t *p, isc_int32_t val) {
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "movl 8(%ebp), %ecx\n"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "movl 12(%ebp), %edx\n"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "xadd %edx, (%ecx)\n"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * set the return value directly in the register so that we
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * can avoid guessing the correct position in the stack for a
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * local variable.
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "movl %edx, %eax"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉isc_atomic_store(isc_int32_t *p, isc_int32_t val) {
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "movl 8(%ebp), %ecx\n"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "movl 12(%ebp), %edx\n"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "xchgl (%ecx), %edx\n"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉isc_atomic_cmpxchg(isc_int32_t *p, isc_int32_t cmpval, isc_int32_t val) {
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "movl 8(%ebp), %ecx\n"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "movl 12(%ebp), %eax\n" /* must be %eax for cmpxchgl */
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "movl 16(%ebp), %edx\n"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 * If (%ecx) == %eax then (%ecx) := %edx.
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 % %eax is set to old (%ecx), which will be the return value.
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉 "cmpxchgl %edx, (%ecx)"
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉#else /* !ISC_PLATFORM_USEGCCASM && !ISC_PLATFORM_USESTDASM */
c528bd698637d84a0081d26a58813607c7f52bb7Tatuya JINMEI 神明達哉#error "unsupported compiler. disable atomic ops by --disable-atomic"
5597be9bb88de138dfec9fa9176708443813925eTatuya JINMEI 神明達哉#endif /* ISC_ATOMIC_H */