// rt/streq.s — string equality at the runtime layer.
//
// Called from cgen for `a == b` / `a != b` when both operands are str.
// SysV ABI: a.ptr in DI, a.len in SI, b.ptr in DX, b.len in CX.
// Returns 1 in AX if equal, 0 otherwise. Caller flips for !=.

TEXT rt_streq,$0
	CMPQ	CX, SI			// lengths must match
	JNE	rt_streq_no
	// SI now holds the (shared) length; iterate while SI > 0
rt_streq_loop:
	CMPQ	$0, SI
	JE	rt_streq_yes
	MOVZBQ	(DI), AX
	MOVZBQ	(DX), R8
	CMPQ	R8, AX
	JNE	rt_streq_no
	ADDQ	$1, DI
	ADDQ	$1, DX
	SUBQ	$1, SI
	JMP	rt_streq_loop
rt_streq_yes:
	MOVQ	$1, AX
	RET
rt_streq_no:
	MOVQ	$0, AX
	RET