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28 lines
1.0 KiB
Plaintext
28 lines
1.0 KiB
Plaintext
/*
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* @(#)sparc.gcc 11.4 (Sleepycat) 9/14/99
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*
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* The ldstub instruction takes the location specified by its first argument
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* (a register containing a memory address) and loads its contents into its
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* second argument (a register) and atomically sets the contents the location
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* specified by its first argument to a byte of 1s. (The value in the second
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* argument is never read, but only overwritten.)
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*
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* The stbar is needed for v8, and is implemented as membar #sync on v9,
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+ so is functional there as well. For v7, stbar may generate an illegal
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+ instruction and we have no way to tell what we're running on. Some
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+ operating systems notice and skip this instruction in the fault handler.
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*
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* For gcc/sparc, 0 is clear, 1 is set.
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*/
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#define MUTEX_SET(tsl) ({ \
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register tsl_t *__l = (tsl); \
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register tsl_t __r; \
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__asm__ volatile \
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("ldstub [%1],%0; stbar" \
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: "=r"( __r) : "r" (__l)); \
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!__r; \
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})
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#define MUTEX_UNSET(tsl) (*(tsl) = 0)
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#define MUTEX_INIT(tsl) MUTEX_UNSET(tsl)
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