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Diffstat (limited to 'erts/include/internal/i386/atomic.h')
| -rw-r--r-- | erts/include/internal/i386/atomic.h | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/erts/include/internal/i386/atomic.h b/erts/include/internal/i386/atomic.h new file mode 100644 index 0000000000..3291ad38e5 --- /dev/null +++ b/erts/include/internal/i386/atomic.h @@ -0,0 +1,155 @@ +/* + * %CopyrightBegin% + * + * Copyright Ericsson AB 2005-2009. All Rights Reserved. + * + * The contents of this file are subject to the Erlang Public License, + * Version 1.1, (the "License"); you may not use this file except in + * compliance with the License. You should have received a copy of the + * Erlang Public License along with this software. If not, it can be + * retrieved online at http://www.erlang.org/. + * + * Software distributed under the License is distributed on an "AS IS" + * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See + * the License for the specific language governing rights and limitations + * under the License. + * + * %CopyrightEnd% + */ + +/* + * Native ethread atomics on x86/x86-64. + * Author: Mikael Pettersson. + * + * This code requires a 486 or newer processor. + */ +#ifndef ETHREAD_I386_ATOMIC_H +#define ETHREAD_I386_ATOMIC_H + +/* An atomic is an aligned long accessed via locked operations. + */ +typedef struct { + volatile long counter; +} ethr_native_atomic_t; + +#ifdef ETHR_TRY_INLINE_FUNCS + +#ifdef __x86_64__ +#define LONG_SUFFIX "q" +#else +#define LONG_SUFFIX "l" +#endif + +static ETHR_INLINE void +ethr_native_atomic_init(ethr_native_atomic_t *var, long i) +{ + var->counter = i; +} +#define ethr_native_atomic_set(v, i) ethr_native_atomic_init((v), (i)) + +static ETHR_INLINE long +ethr_native_atomic_read(ethr_native_atomic_t *var) +{ + return var->counter; +} + +static ETHR_INLINE void +ethr_native_atomic_add(ethr_native_atomic_t *var, long incr) +{ + __asm__ __volatile__( + "lock; add" LONG_SUFFIX " %1, %0" + : "=m"(var->counter) + : "ir"(incr), "m"(var->counter)); +} + +static ETHR_INLINE void +ethr_native_atomic_inc(ethr_native_atomic_t *var) +{ + __asm__ __volatile__( + "lock; inc" LONG_SUFFIX " %0" + : "=m"(var->counter) + : "m"(var->counter)); +} + +static ETHR_INLINE void +ethr_native_atomic_dec(ethr_native_atomic_t *var) +{ + __asm__ __volatile__( + "lock; dec" LONG_SUFFIX " %0" + : "=m"(var->counter) + : "m"(var->counter)); +} + +static ETHR_INLINE long +ethr_native_atomic_add_return(ethr_native_atomic_t *var, long incr) +{ + long tmp; + + tmp = incr; + __asm__ __volatile__( + "lock; xadd" LONG_SUFFIX " %0, %1" /* xadd didn't exist prior to the 486 */ + : "=r"(tmp) + : "m"(var->counter), "0"(tmp)); + /* now tmp is the atomic's previous value */ + return tmp + incr; +} + +#define ethr_native_atomic_inc_return(var) ethr_native_atomic_add_return((var), 1) +#define ethr_native_atomic_dec_return(var) ethr_native_atomic_add_return((var), -1) + +static ETHR_INLINE long +ethr_native_atomic_cmpxchg(ethr_native_atomic_t *var, long new, long old) +{ + __asm__ __volatile__( + "lock; cmpxchg" LONG_SUFFIX " %2, %3" + : "=a"(old), "=m"(var->counter) + : "r"(new), "m"(var->counter), "0"(old) + : "cc", "memory"); /* full memory clobber to make this a compiler barrier */ + return old; +} + +static ETHR_INLINE long +ethr_native_atomic_and_retold(ethr_native_atomic_t *var, long mask) +{ + long tmp, old; + + tmp = var->counter; + do { + old = tmp; + tmp = ethr_native_atomic_cmpxchg(var, tmp & mask, tmp); + } while (__builtin_expect(tmp != old, 0)); + /* now tmp is the atomic's previous value */ + return tmp; +} + +static ETHR_INLINE long +ethr_native_atomic_or_retold(ethr_native_atomic_t *var, long mask) +{ + long tmp, old; + + tmp = var->counter; + do { + old = tmp; + tmp = ethr_native_atomic_cmpxchg(var, tmp | mask, tmp); + } while (__builtin_expect(tmp != old, 0)); + /* now tmp is the atomic's previous value */ + return tmp; +} + +static ETHR_INLINE long +ethr_native_atomic_xchg(ethr_native_atomic_t *var, long val) +{ + long tmp = val; + __asm__ __volatile__( + "xchg" LONG_SUFFIX " %0, %1" + : "=r"(tmp) + : "m"(var->counter), "0"(tmp)); + /* now tmp is the atomic's previous value */ + return tmp; +} + +#undef LONG_SUFFIX + +#endif /* ETHR_TRY_INLINE_FUNCS */ + +#endif /* ETHREAD_I386_ATOMIC_H */ |