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re PR libstdc++/5198 (3.0.3 linux x m68k build fail: invalid opcodes in c++locale.cc) 

PR libstdc++/5198
        * config/cpu/m68k/bits/atomicity.h (__exchange_and_add): Only use
        CAS on the cpu variants that support it.  Add versions that use
        TAS and that disable interrupts.
        (__atomic_add): Use __exchange_and_add to guarantee atomicity.

From-SVN: r49160
This commit is contained in:
Richard Henderson 2002-01-23 17:31:13 -08:00 committed by Richard Henderson
parent 88a446c036
commit acae253ec1
2 changed files with 93 additions and 10 deletions
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8
libstdc++-v3/ChangeLog
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@ -1,3 +1,11 @@
2002-01-23 Richard Henderson <rth@redhat.com>
PR libstdc++/5198
* config/cpu/m68k/bits/atomicity.h (__exchange_and_add): Only use
CAS on the cpu variants that support it. Add versions that use
TAS and that disable interrupts.
(__atomic_add): Use __exchange_and_add to guarantee atomicity.
2002-01-23 Matt Kraai <kraai@alumni.cmu.edu>
* include/bits/locale_facets.tcc: Remove old comments.

95
libstdc++-v3/config/cpu/m68k/bits/atomicity.h
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@ -1,6 +1,6 @@
// Low-level functions for atomic operations: m680x0, x >= 2 version -*- C++ -*-
// Low-level functions for atomic operations: m68k version -*- C++ -*-
// Copyright (C) 2001 Free Software Foundation, Inc.
// Copyright (C) 2001, 2002 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
@ -32,30 +32,105 @@
typedef int _Atomic_word;
#if defined(__mc68020__) || defined(__mc68030__) \
|| defined(__mc68040__) || defined(__mc68060__)
// These variants support compare-and-swap.
static inline _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;"
" add%.l %2,%1;"
" cas%.l %0,%1,%3;"
" jbne 1b"
__asm__ __volatile__ ("1: move%.l %0,%1\n\t"
"add%.l %2,%1\n\t"
"cas%.l %0,%1,%3\n\t"
"jbne 1b"
: "=d" (__result), "=&d" (__temp)
: "d" (__val), "m" (*__mem), "0" (__result)
: "memory");
return __result;
}
#elif !defined(__mcf5200__) && !defined(__mcf5300__)
// 68000, 68010, cpu32 and 5400 support test-and-set.
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;
static inline _Atomic_word
__attribute__ ((__unused__))
__exchange_and_add (volatile _Atomic_word *__mem, int __val)
{
_Atomic_word __result;
__asm__ __volatile__("1: tas %0\n\tjbne 1b"
: "=m"(__Atomicity_lock<0>::_S_atomicity_lock)
: "m"(__Atomicity_lock<0>::_S_atomicity_lock));
__result = *__mem;
*__mem = __result + __val;
__Atomicity_lock<0>::_S_atomicity_lock = 0;
return __result;
}
#else
// These variants do not support any atomic operations at all.
// The best we can hope for is to disable interrupts, which we
// can only do from supervisor mode.
#if defined(__rtems__) || defined(__vxWorks__) || defined(__embedded__)
static inline _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
#warning "__exchange_and_add is not atomic for this target"
static inline _Atomic_word
__attribute__ ((__unused__))
__exchange_and_add (volatile _Atomic_word *__mem, int __val)
{
_Atomic_word __result;
__result = *__mem;
*__mem = __result + __val;
return __result;
}
#endif /* embedded */
#endif /* CAS / TAS / IRQ */
static inline void
__attribute__ ((__unused__))
__atomic_add (volatile _Atomic_word* __mem, int __val)
{
__asm__ __volatile__ ("add%.l %0,%1"
: : "id" (__val), "m" (*__mem) : "memory");
// Careful: using add.l with a memory destination is not
// architecturally guaranteed to be atomic.
(void) __exchange_and_add (__mem, __val);
}
#endif /* atomicity.h */