git: 9front

ref: 4cd2e7321078a1407a35ea4ea4c06583d80b2a0a
dir: /sys/src/libc/spim/tas.s/

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/*
 *	4K tas for spim
 */

#define	LL(base, rt)	WORD	$((060<<26)|((base)<<21)|((rt)<<16))
#define	SC(base, rt)	WORD	$((070<<26)|((base)<<21)|((rt)<<16))
#define	NOOP		WORD	$0x27

	TEXT	_tas(SB), $0
	MOVW	R1, R2		/* address of key */
tas1:
	MOVW	$1, R3
	LL(2, 1)
	NOOP
	SC(2, 3)
	NOOP
	BEQ	R3, tas1
	RET