| // Low-level functions for atomic operations: m68k version -*- C++ -*- |
| |
| // Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 2, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License along |
| // with this library; see the file COPYING. If not, write to the Free |
| // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
| // USA. |
| |
| // As a special exception, you may use this file as part of a free software |
| // library without restriction. Specifically, if other files instantiate |
| // templates or use macros or inline functions from this file, or you compile |
| // this file and link it with other files to produce an executable, this |
| // file does not by itself cause the resulting executable to be covered by |
| // the GNU General Public License. This exception does not however |
| // invalidate any other reasons why the executable file might be covered by |
| // the GNU General Public License. |
| |
| #include <bits/atomicity.h> |
| |
| namespace __gnu_cxx |
| { |
| #if ( defined(__mc68020__) || defined(__mc68030__) \ |
| || defined(__mc68040__) || defined(__mc68060__) ) \ |
| && !defined(__mcpu32__) |
| // These variants support compare-and-swap. |
| _Atomic_word |
| __attribute__ ((__unused__)) |
| __exchange_and_add(volatile _Atomic_word* __mem, int __val) |
| { |
| register _Atomic_word __result = *__mem; |
| register _Atomic_word __temp; |
| __asm__ __volatile__ ("1: move%.l %0,%1\n\t" |
| "add%.l %3,%1\n\t" |
| "cas%.l %0,%1,%2\n\t" |
| "jne 1b" |
| : "=d" (__result), "=&d" (__temp), "=m" (*__mem) |
| : "d" (__val), "0" (__result), "m" (*__mem)); |
| return __result; |
| } |
| |
| #elif defined(__rtems__) |
| // TAS/JBNE is unsafe on systems with strict priority-based scheduling. |
| // Disable interrupts, which we can do only from supervisor mode. |
| _Atomic_word |
| __attribute__ ((__unused__)) |
| __exchange_and_add(volatile _Atomic_word* __mem, int __val) |
| { |
| _Atomic_word __result; |
| short __level, __tmpsr; |
| __asm__ __volatile__ ("move%.w %%sr,%0\n\tor%.l %0,%1\n\tmove%.w %1,%%sr" |
| : "=d"(__level), "=d"(__tmpsr) : "1"(0x700)); |
| |
| __result = *__mem; |
| *__mem = __result + __val; |
| __asm__ __volatile__ ("move%.w %0,%%sr" : : "d"(__level)); |
| |
| return __result; |
| } |
| |
| #else |
| |
| template<int __inst> |
| struct _Atomicity_lock |
| { |
| static volatile unsigned char _S_atomicity_lock; |
| }; |
| |
| template<int __inst> |
| volatile unsigned char _Atomicity_lock<__inst>::_S_atomicity_lock = 0; |
| |
| template volatile unsigned char _Atomicity_lock<0>::_S_atomicity_lock; |
| |
| _Atomic_word |
| __attribute__ ((__unused__)) |
| __exchange_and_add(volatile _Atomic_word* __mem, int __val) |
| { |
| _Atomic_word __result; |
| |
| // bset with no immediate addressing (not SMP-safe) |
| #if defined(__mcf5200__) || defined(__mcf5300__) |
| __asm__ __volatile__("1: bset.b #7,%0@\n\tjbne 1b" |
| : /* no outputs */ |
| : "a"(&_Atomicity_lock<0>::_S_atomicity_lock) |
| : "cc", "memory"); |
| |
| // CPU32 and MCF5400 support test-and-set (SMP-safe). |
| #elif defined(__mcpu32__) || defined(__mcf5400__) |
| __asm__ __volatile__("1: tas %0\n\tjbne 1b" |
| : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) |
| : /* none */ |
| : "cc"); |
| |
| // Use bset with immediate addressing for 68000/68010 (not SMP-safe) |
| // NOTE: TAS is available on the 68000, but unsupported by some Amiga |
| // memory controllers. |
| #else |
| __asm__ __volatile__("1: bset.b #7,%0\n\tjbne 1b" |
| : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) |
| : /* none */ |
| : "cc"); |
| #endif |
| |
| __result = *__mem; |
| *__mem = __result + __val; |
| |
| _Atomicity_lock<0>::_S_atomicity_lock = 0; |
| |
| return __result; |
| } |
| |
| #endif /* TAS / BSET */ |
| |
| void |
| __attribute__ ((__unused__)) |
| __atomic_add(volatile _Atomic_word* __mem, int __val) |
| { |
| // Careful: using add.l with a memory destination is not |
| // architecturally guaranteed to be atomic. |
| __exchange_and_add(__mem, __val); |
| } |
| } // namespace __gnu_cxx |