1117397Skan// Low-level functions for atomic operations: m68k version -*- C++ -*- 2117397Skan 3169691Skan// Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. 4117397Skan// 5117397Skan// This file is part of the GNU ISO C++ Library. This library is free 6117397Skan// software; you can redistribute it and/or modify it under the 7117397Skan// terms of the GNU General Public License as published by the 8117397Skan// Free Software Foundation; either version 2, or (at your option) 9117397Skan// any later version. 10117397Skan 11117397Skan// This library is distributed in the hope that it will be useful, 12117397Skan// but WITHOUT ANY WARRANTY; without even the implied warranty of 13117397Skan// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14117397Skan// GNU General Public License for more details. 15117397Skan 16117397Skan// You should have received a copy of the GNU General Public License along 17117397Skan// with this library; see the file COPYING. If not, write to the Free 18169691Skan// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 19117397Skan// USA. 20117397Skan 21117397Skan// As a special exception, you may use this file as part of a free software 22117397Skan// library without restriction. Specifically, if other files instantiate 23117397Skan// templates or use macros or inline functions from this file, or you compile 24117397Skan// this file and link it with other files to produce an executable, this 25117397Skan// file does not by itself cause the resulting executable to be covered by 26117397Skan// the GNU General Public License. This exception does not however 27117397Skan// invalidate any other reasons why the executable file might be covered by 28117397Skan// the GNU General Public License. 29117397Skan 30169691Skan#include <ext/atomicity.h> 31117397Skan 32169691Skan_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 33169691Skan 34122182Skan#if ( defined(__mc68020__) || defined(__mc68030__) \ 35122182Skan || defined(__mc68040__) || defined(__mc68060__) ) \ 36122182Skan && !defined(__mcpu32__) 37132720Skan // These variants support compare-and-swap. 38132720Skan _Atomic_word 39132720Skan __attribute__ ((__unused__)) 40132720Skan __exchange_and_add(volatile _Atomic_word* __mem, int __val) 41132720Skan { 42132720Skan register _Atomic_word __result = *__mem; 43132720Skan register _Atomic_word __temp; 44132720Skan __asm__ __volatile__ ("1: move%.l %0,%1\n\t" 45132720Skan "add%.l %3,%1\n\t" 46132720Skan "cas%.l %0,%1,%2\n\t" 47132720Skan "jne 1b" 48132720Skan : "=d" (__result), "=&d" (__temp), "=m" (*__mem) 49132720Skan : "d" (__val), "0" (__result), "m" (*__mem)); 50132720Skan return __result; 51132720Skan } 52117397Skan 53117397Skan#elif defined(__rtems__) 54132720Skan // TAS/JBNE is unsafe on systems with strict priority-based scheduling. 55132720Skan // Disable interrupts, which we can do only from supervisor mode. 56132720Skan _Atomic_word 57132720Skan __attribute__ ((__unused__)) 58132720Skan __exchange_and_add(volatile _Atomic_word* __mem, int __val) 59132720Skan { 60132720Skan _Atomic_word __result; 61132720Skan short __level, __tmpsr; 62132720Skan __asm__ __volatile__ ("move%.w %%sr,%0\n\tor%.l %0,%1\n\tmove%.w %1,%%sr" 63132720Skan : "=d"(__level), "=d"(__tmpsr) : "1"(0x700)); 64132720Skan 65132720Skan __result = *__mem; 66132720Skan *__mem = __result + __val; 67132720Skan __asm__ __volatile__ ("move%.w %0,%%sr" : : "d"(__level)); 68132720Skan 69132720Skan return __result; 70132720Skan } 71117397Skan 72132720Skan#else 73132720Skan 74132720Skan template<int __inst> 75132720Skan struct _Atomicity_lock 76132720Skan { 77132720Skan static volatile unsigned char _S_atomicity_lock; 78132720Skan }; 79117397Skan 80132720Skan template<int __inst> 81132720Skan volatile unsigned char _Atomicity_lock<__inst>::_S_atomicity_lock = 0; 82132720Skan 83132720Skan template volatile unsigned char _Atomicity_lock<0>::_S_atomicity_lock; 84132720Skan 85132720Skan _Atomic_word 86132720Skan __attribute__ ((__unused__)) 87132720Skan __exchange_and_add(volatile _Atomic_word* __mem, int __val) 88132720Skan { 89132720Skan _Atomic_word __result; 90132720Skan 91132720Skan // bset with no immediate addressing (not SMP-safe) 92132720Skan#if defined(__mcf5200__) || defined(__mcf5300__) 93132720Skan __asm__ __volatile__("1: bset.b #7,%0@\n\tjbne 1b" 94132720Skan : /* no outputs */ 95132720Skan : "a"(&_Atomicity_lock<0>::_S_atomicity_lock) 96132720Skan : "cc", "memory"); 97132720Skan 98132720Skan // CPU32 and MCF5400 support test-and-set (SMP-safe). 99132720Skan#elif defined(__mcpu32__) || defined(__mcf5400__) 100132720Skan __asm__ __volatile__("1: tas %0\n\tjbne 1b" 101132720Skan : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) 102132720Skan : /* none */ 103132720Skan : "cc"); 104132720Skan 105132720Skan // Use bset with immediate addressing for 68000/68010 (not SMP-safe) 106132720Skan // NOTE: TAS is available on the 68000, but unsupported by some Amiga 107132720Skan // memory controllers. 108122182Skan#else 109132720Skan __asm__ __volatile__("1: bset.b #7,%0\n\tjbne 1b" 110132720Skan : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) 111132720Skan : /* none */ 112132720Skan : "cc"); 113122182Skan#endif 114132720Skan 115132720Skan __result = *__mem; 116132720Skan *__mem = __result + __val; 117132720Skan 118132720Skan _Atomicity_lock<0>::_S_atomicity_lock = 0; 119132720Skan 120132720Skan return __result; 121132720Skan } 122132720Skan 123122182Skan#endif /* TAS / BSET */ 124117397Skan 125132720Skan void 126132720Skan __attribute__ ((__unused__)) 127132720Skan __atomic_add(volatile _Atomic_word* __mem, int __val) 128132720Skan { 129132720Skan // Careful: using add.l with a memory destination is not 130132720Skan // architecturally guaranteed to be atomic. 131132720Skan __exchange_and_add(__mem, __val); 132132720Skan } 133169691Skan 134169691Skan_GLIBCXX_END_NAMESPACE 135