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/*
* Copyright (C) 2005 Internet Systems Consortium, Inc. ("ISC")
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: atomic.h,v 1.1.2.1 2005/07/09 07:14:00 jinmei Exp $ */
#ifndef ISC_ATOMIC_H
#define ISC_ATOMIC_H 1
#include <isc/platform.h>
#include <isc/types.h>
#ifdef ISC_PLATFORM_USEGCCASM
/*
* This routine atomically increments the value stored in 'p' by 'val', and
* returns the previous value.
*/
static inline isc_int32_t
isc_atomic_xadd(isc_int32_t *p, int val) {
isc_int32_t orig;
/* add is a cheat, since MIPS has no mov instruction */
__asm__ volatile (
"1:"
"ll $3, %1\n"
"add %0, $0, $3\n"
"add $3, $3, %2\n"
"sc $3, %1\n"
"beq $3, 0, 1b"
: "=&r"(orig)
: "m"(*p), "r"(val)
: "memory", "$3"
);
return (orig);
}
/*
* This routine atomically stores the value 'val' in 'p'.
*/
static inline void
isc_atomic_store(isc_int32_t *p, isc_int32_t val) {
__asm__ volatile (
"1:"
"ll $3, %0\n"
"add $3, $0, %1\n"
"sc $3, %0\n"
"beq $3, 0, 1b"
:
: "m"(*p), "r"(val)
: "memory", "$3"
);
}
/*
* This routine atomically replaces the value in 'p' with 'val', if the
* original value is equal to 'cmpval'. The original value is returned in any
* case.
*/
static inline isc_int32_t
isc_atomic_cmpxchg(isc_int32_t *p, int cmpval, int val) {
isc_int32_t orig;
__asm__ volatile(
"1:"
"ll $3, %1\n"
"add %0, $0, $3\n"
"bne $3, %2, 2f\n"
"add $3, $0, %3\n"
"sc $3, %1\n"
"beq $3, 0, 1b\n"
"2:"
: "=&r"(orig)
: "m"(*p), "r"(cmpval), "r"(val)
: "memory", "$3"
);
return (orig);
}
#else /* !ISC_PLATFORM_USEGCCASM */
#error "unsupported compiler. disable atomic ops by --disable-atomic"
#endif
#endif /* ISC_ATOMIC_H */
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