26 lines
784 B
C
26 lines
784 B
C
#ifndef COSMOPOLITAN_LIBC_BITS_XCHG_H_
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#define COSMOPOLITAN_LIBC_BITS_XCHG_H_
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#include "libc/str/str.h"
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#if !(__ASSEMBLER__ + __LINKER__ + 0)
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/**
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* Exchanges *MEMORY into *LOCALVAR.
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*
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* @return *MEMORY
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* @see lockcmpxchg()
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* todo(jart): what's the point of this?
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*/
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#define xchg(MEMORY, LOCALVAR) \
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({ \
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autotype(MEMORY) Memory = (MEMORY); \
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typeof(Memory) LocalVar = (LOCALVAR); \
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typeof(*Memory) Temp; \
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memcpy(&Temp, Memory, sizeof(Temp)); \
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memcpy(Memory, LocalVar, sizeof(Temp)); \
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memcpy(LocalVar, &Temp, sizeof(Temp)); \
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Temp; \
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})
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#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
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#endif /* COSMOPOLITAN_LIBC_BITS_XCHG_H_ */
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