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/***********************************************************************/
/* */
/* OCaml */
/* */
/* Xavier Leroy and Damien Doligez, INRIA Rocquencourt */
/* */
/* Copyright 1996 Institut National de Recherche en Informatique et */
/* en Automatique. All rights reserved. This file is distributed */
/* under the terms of the GNU Library General Public License, with */
/* the special exception on linking described in file ../LICENSE. */
/* */
/***********************************************************************/
/* Processor-specific operation: atomic "read and clear" */
#ifndef CAML_SIGNALS_MACHDEP_H
#define CAML_SIGNALS_MACHDEP_H
#if defined(__GNUC__) && defined(__ATOMIC_SEQ_CST) \
&& defined(__GCC_ATOMIC_LONG_LOCK_FREE)
/* Use the "atomic" builtins of GCC and Clang */
#define Read_and_clear(dst,src) \
((dst) = __atomic_exchange_n(&(src), 0, __ATOMIC_SEQ_CST))
#elif defined(__GNUC__) && (defined(__i386__) || (defined(__x86_64__) \
&& defined(__ILP32__)))
#define Read_and_clear(dst,src) \
asm("xorl %0, %0; xchgl %0, %1" \
: "=r" (dst), "=m" (src) \
: "m" (src))
#elif defined(__GNUC__) && defined(__x86_64__)
#define Read_and_clear(dst,src) \
asm("xorq %0, %0; xchgq %0, %1" \
: "=r" (dst), "=m" (src) \
: "m" (src))
#elif defined(__GNUC__) && defined(__ppc__)
#define Read_and_clear(dst,src) \
asm("0: lwarx %0, 0, %1\n\t" \
"stwcx. %2, 0, %1\n\t" \
"bne- 0b" \
: "=&r" (dst) \
: "r" (&(src)), "r" (0) \
: "cr0", "memory")
#elif defined(__GNUC__) && defined(__ppc64__)
#define Read_and_clear(dst,src) \
asm("0: ldarx %0, 0, %1\n\t" \
"stdcx. %2, 0, %1\n\t" \
"bne- 0b" \
: "=&r" (dst) \
: "r" (&(src)), "r" (0) \
: "cr0", "memory")
#else
/* Default, non-atomic implementation */
#define Read_and_clear(dst,src) ((dst) = (src), (src) = 0)
#endif
#endif /* CAML_SIGNALS_MACHDEP_H */
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