git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1315 b08c6af1-5177-4d33-ba66-4b1c6b8b522a
		
			
				
	
	
		
			130 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			130 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/**********************************************************************
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                       The OPTYap Prolog system                
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  OPTYap extends the Yap Prolog system to support or-parallel tabling
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  Copyright:   R. Rocha and NCC - University of Porto, Portugal
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  File:        alpha_locks_funcs.h  
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  version:     $Id: alpha_locks_funcs.h,v 1.2 2005-05-31 08:24:24 ricroc Exp $   
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**********************************************************************/
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/* ------------------------------- **
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**      Atomic lock for ALPHA      **
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** ------------------------------- */
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/* This code is stolen from the Linux kernel */
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static __inline__ int _test_and_set_bit(unsigned long nr,
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				       volatile void * addr)
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{
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	unsigned long oldbit;
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	unsigned long temp;
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	unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
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	__asm__ __volatile__(
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	"1:	ldl_l %0,%1\n"
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	"	and %0,%3,%2\n"
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	"	bne %2,2f\n"
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	"	xor %0,%3,%0\n"
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	"	stl_c %0,%1\n"
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	"	beq %0,3f\n"
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	"	mb\n"
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	"2:\n"
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	".subsection 2\n"
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	"3:	br 1b\n"
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	".previous"
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	:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
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	:"Ir" (1UL << (nr & 31)), "m" (*m));
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	return oldbit != 0;
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}
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static __inline__ void _spin_lock(volatile void *lock)
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{
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	long tmp;
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	/* Use sub-sections to put the actual loop at the end
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	   of this object file's text section so as to perfect
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	   branch prediction.  */
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	__asm__ __volatile__(
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	"1:	ldl_l	%0,%1\n"
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	"	blbs	%0,2f\n"
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	"	or	%0,1,%0\n"
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	"	stl_c	%0,%1\n"
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	"	beq	%0,2f\n"
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	"	mb\n"
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	".subsection 2\n"
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	"2:	ldl	%0,%1\n"
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	"	blbs	%0,2b\n"
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	"	br	1b\n"
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	".previous"
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	: "=r" (tmp), "=m" (__dummy_lock(lock))
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	: "m"(__dummy_lock(lock)));
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}
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static inline void _write_lock(rwlock_t * lock)
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{
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	long regx;
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	__asm__ __volatile__(
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	"1:	ldl_l	%1,%0\n"
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	"	bne	%1,6f\n"
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	"	or	$31,1,%1\n"
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	"	stl_c	%1,%0\n"
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	"	beq	%1,6f\n"
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	"	mb\n"
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	".subsection 2\n"
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	"6:	ldl	%1,%0\n"
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	"	bne	%1,6b\n"
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	"	br	1b\n"
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	".previous"
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	: "=m" (__dummy_lock(lock)), "=&r" (regx)
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	: "0" (__dummy_lock(lock))
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	);
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}
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static inline void _read_lock(rwlock_t * lock)
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{
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	long regx;
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	__asm__ __volatile__(
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	"1:	ldl_l	%1,%0\n"
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	"	blbs	%1,6f\n"
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	"	subl	%1,2,%1\n"
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	"	stl_c	%1,%0\n"
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	"	beq	%1,6f\n"
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	"4:	mb\n"
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	".subsection 2\n"
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	"6:	ldl	%1,%0\n"
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	"	blbs	%1,6b\n"
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	"	br	1b\n"
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	".previous"
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	: "=m" (__dummy_lock(lock)), "=&r" (regx)
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	: "m" (__dummy_lock(lock))
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	);
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}
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static inline void _write_unlock(rwlock_t * lock)
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{
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	mb();
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	*(volatile int *)lock = 0;
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}
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static inline void _read_unlock(rwlock_t * lock)
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{
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	long regx;
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	__asm__ __volatile__(
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	"1:	ldl_l	%1,%0\n"
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	"	addl	%1,2,%1\n"
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	"	stl_c	%1,%0\n"
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	"	beq	%1,6f\n"
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	".subsection 2\n"
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	"6:	br	1b\n"
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	".previous"
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	: "=m" (__dummy_lock(lock)), "=&r" (regx)
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	: "m" (__dummy_lock(lock)));
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}
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