/* * return from user-mode exception. * expects new SPSR in R0.  R13 must point to ureg->type. */_rfue:TEXT rfue(SB), 1, $-4//	CPSID//	BIC	$PsrMbz, R0		/* force little-endian upon return */	MOVW	R0, SPSR		/* ... */ 	/*	 * order on stack is type, psr, pc, but RFEV7 needs pc, psr.	 * step on type and previous word to hold temporary values.	 * we could instead change the order in which psr & pc are pushed.	 */	MOVW	4(R13), R1		/* psr */	MOVW	8(R13), R2		/* pc */	MOVW	R2, 4(R13)		/* pc */	MOVW	R1, 8(R13)		/* psr */ 	MOVM.DB.S (R13), [R0-R14]	/* restore user registers */	ADD	$4, R13			/* pop type, sp -> pc */ #ifdef OLDWAY	ADD	$(2*4), R13		/* pop past ureg->{type+psr} to pc */	/*	 * this used to work on arm arch v[567] and still works on cpu 0.	 * for some reason it sometimes sets PsrBigend on cpu 1.	 * Ureg's tail was:	 *	 * typedef struct Ureg {	 * 	⋯	 * 	ulong	type;	/* of exception */	 * 	ulong	psr;	 * 	ulong	pc;	/* interrupted addr */	 * } Ureg;	 */	RFE				/* MOVM.IA.S.W (R13), [R15] */#endif//	SETEND(0)	RFEV7W(13)