/* * Copyright (C) 2005, 2007 Internet Systems Consortium, Inc. ("ISC") * * Permission to use, copy, modify, and/or 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 1.3 2007/06/19 23:47:18 tbox 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 */ |