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/*
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 *	R4000 user-level atomic operations
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 */
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#define	LL(base, rt)	WORD	$((060<<26)|((base)<<21)|((rt)<<16))
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#define	SC(base, rt)	WORD	$((070<<26)|((base)<<21)|((rt)<<16))
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#define	NOOP		WORD	$0x27
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TEXT ainc(SB), 1, $-4			/* long ainc(long *); */
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TEXT _xinc(SB), 1, $-4			/* void _xinc(long *); */
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	MOVW	R1, R2			/* address of counter */
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loop:	MOVW	$1, R3
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	LL(2, 1)
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	NOOP
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	ADDU	R1, R3
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	MOVW	R3, R1			/* return new value */
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	SC(2, 3)
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	NOOP
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	BEQ	R3,loop
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	RET
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TEXT adec(SB), 1, $-4			/* long adec(long*); */
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TEXT _xdec(SB), 1, $-4			/* long _xdec(long *); */
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	MOVW	R1, R2			/* address of counter */
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loop1:	MOVW	$-1, R3
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	LL(2, 1)
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	NOOP
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	ADDU	R1, R3
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	MOVW	R3, R1			/* return new value */
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	SC(2, 3)
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	NOOP
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	BEQ	R3,loop1
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	RET
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/*
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 * int cas(uint* p, int ov, int nv);
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 */
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TEXT cas(SB), 1, $-4
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	MOVW	ov+4(FP), R2
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	MOVW	nv+8(FP), R3
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spincas:
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	LL(1, 4)			/* R4 = *R1 */
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	NOOP
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	BNE	R2, R4, fail
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	SC(1, 3)			/* *R1 = R3 */
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	NOOP
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	BEQ	R3, spincas		/* R3 == 0 means store failed */
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	MOVW	$1, R1
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	RET
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fail:
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	MOVW	$0, R1
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	RET