xref: /onnv-gate/usr/src/lib/libc/sparc/sys/_lwp_mutex_unlock.s (revision 7298:b69e27387f74)
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214574Sraf
220Sstevel@tonic-gate/*
236515Sraf * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
240Sstevel@tonic-gate * Use is subject to license terms.
250Sstevel@tonic-gate */
260Sstevel@tonic-gate
27*7298SMark.J.Nelson@Sun.COM	.file	"_lwp_mutex_unlock.s"
280Sstevel@tonic-gate
290Sstevel@tonic-gate#include "SYS.h"
300Sstevel@tonic-gate#include <../assym.h>
310Sstevel@tonic-gate
320Sstevel@tonic-gate	ENTRY(_lwp_mutex_unlock)
330Sstevel@tonic-gate	membar	#LoadStore|#StoreStore
340Sstevel@tonic-gate	add	%o0, MUTEX_LOCK_WORD, %o1
350Sstevel@tonic-gate	ld	[%o1], %o2
360Sstevel@tonic-gate1:
370Sstevel@tonic-gate	clr	%o3				! clear lock/get waiter field
380Sstevel@tonic-gate	cas	[%o1], %o2, %o3			! atomically
390Sstevel@tonic-gate	cmp	%o2, %o3
400Sstevel@tonic-gate	bne,a,pn %icc, 1b
410Sstevel@tonic-gate	  mov	%o3, %o2
420Sstevel@tonic-gate	btst	WAITER_MASK, %o3		! check for waiters
430Sstevel@tonic-gate	beq,a,pt %icc,2f			! if no waiters
440Sstevel@tonic-gate	  clr 	%o0				! 	return 0
450Sstevel@tonic-gate						! else (note that %o0 is still
460Sstevel@tonic-gate						!	&mutex)
474574Sraf	clr	%o1				! call kernel to wakeup waiter:
484574Sraf	SYSTRAP_RVAL1(lwp_mutex_wakeup)		!    lwp_mutex_wakeup(mp, 0)
490Sstevel@tonic-gate	SYSLWPERR
500Sstevel@tonic-gate2: 	RET
510Sstevel@tonic-gate	SET_SIZE(_lwp_mutex_unlock)
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