1/*
2Copyright (c) 2009 Nick Clifton <nickc@redhat.com>
3 */
4#include <picolibc.h>
5
6	.file	"strlen.S"
7
8	.section .text
9
10	.global  _strlen
11	.type	 _strlen,@function
12_strlen:
13#ifdef __RX_DISALLOW_STRING_INSNS__
14	mov	r1, r4
15
161:	mov.b	[r1+], r5
17	cmp	#0, r5
18	bne	1b
19
20	sub	#1, r1
21	sub	r4, r1
22	rts
23#else
24	add	#0, r1, r4	; Save a copy of the string start address and set the condition flags.
25	beq     null_string	; Test for a NULL pointer.
26	mov	#-1, r3		; Set a limit on the number of bytes examined.
27	mov	#0,  r2		; Stop searching when we find a NUL byte.
28	suntil.b     		; Search until *r1 == r2
29	sub	#1, r1		; suntil.b leaves r1 pointing to the byte beyond the match.
30null_string:
31	sub	r4, r1		; Compute the length.
32	rts
33#endif
34	.size _strlen, . - _strlen
35