/* * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved. * * The contents of this file constitute Original Code as defined in and are * subject to the Apple Public Source License Version 1.2 (the 'License'). * You may not use this file except in compliance with the License. Please obtain * a copy of the License at http://www.apple.com/publicsource and read it before * using this file. * * This Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the * specific language governing rights and limitations under the License. */ // // threading_internal - internal support classes and functions for threading implementation // #ifndef _H_THREADING_INTERNAL #define _H_THREADING_INTERNAL #include <Security/utilities.h> namespace Security { // // Architecture-specific atomic operation primitives. // AtomicWord is an integer type that works with these; // we'll assume that a pointer fits into it (using reinterpret_cast). // #if TARGET_CPU_PPC #define _HAVE_ATOMIC_OPERATIONS typedef unsigned int AtomicWord; inline AtomicWord atomicLoad(AtomicWord &atom) { AtomicWord result; asm volatile ( "0: lwarx %0,0,%1 \n" " stwcx. %0,0,%1 \n" " bne- 0b" : "=&r"(result) : "b"(&atom) : "cc" ); return result; } inline AtomicWord atomicStore(AtomicWord &atom, AtomicWord newValue, AtomicWord oldValue) { register bool result; asm volatile ( "0: lwarx %0,0,%1 \n" // load and reserve -> %0 " cmpw %0,%3 \n" // compare to old " bne 1f \n" // fail if not equal " stwcx. %2,0,%1 \n" // store and check " bne 0b \n" // retry if contended "1: " : "=&r"(result) : "b"(&atom), "r"(newValue), "r"(oldValue) : "cc" ); return result; } inline AtomicWord atomicOffset(AtomicWord &atom, int offset) { AtomicWord result; asm volatile ( "0: lwarx %0,0,%1 \n" " add %0,%0,%2 \n" " stwcx. %0,0,%1 \n" " bne- 0b" : "=&r"(result) : "b"(&atom), "r"(offset) : "cc" ); return result; } inline AtomicWord atomicIncrement(AtomicWord &atom) { return atomicOffset(atom, +1); } inline AtomicWord atomicDecrement(AtomicWord &atom) { return atomicOffset(atom, -1); } #endif //TARGET_CPU_PPC } // end namespace Security #endif //_H_THREADING_INTERNAL