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