mirror of
https://github.com/jart/cosmopolitan.git
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fa20edc44d
- Remove most __ASSEMBLER__ __LINKER__ ifdefs - Rename libc/intrin/bits.h to libc/serialize.h - Block pthread cancelation in fchmodat() polyfill - Remove `clang-format off` statements in third_party
26 lines
1.3 KiB
C
26 lines
1.3 KiB
C
#ifndef COSMOPOLITAN_LIBC_INTRIN_CMPXCHG_H_
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#define COSMOPOLITAN_LIBC_INTRIN_CMPXCHG_H_
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#include "libc/intrin/asmflag.h"
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COSMOPOLITAN_C_START_
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#if defined(__GNUC__) && !defined(__STRICT_ANSI__) && defined(__x86__)
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#define _cmpxchg(IFTHING, ISEQUALTOME, REPLACEITWITHME) \
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({ \
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bool32 DidIt; \
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autotype(IFTHING) IfThing = (IFTHING); \
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typeof(*IfThing) IsEqualToMe = (ISEQUALTOME); \
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typeof(*IfThing) ReplaceItWithMe = (REPLACEITWITHME); \
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asm volatile(ZFLAG_ASM("cmpxchg\t%3,%1") \
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: ZFLAG_CONSTRAINT(DidIt), "+m"(*IfThing), "+a"(IsEqualToMe) \
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: "r"(ReplaceItWithMe) \
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: "cc"); \
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DidIt; \
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})
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#else
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#define _cmpxchg(IFTHING, ISEQUALTOME, REPLACEITWITHME) \
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(*(IFTHING) == (ISEQUALTOME) ? (*(IFTHING) = (REPLACEITWITHME), 1) : 0)
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#endif
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COSMOPOLITAN_C_END_
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#endif /* COSMOPOLITAN_LIBC_INTRIN_CMPXCHG_H_ */
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