xref: /openbmc/linux/arch/ia64/lib/strnlen_user.S (revision d3964221)
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Returns 0 if exception before NUL or reaching the supplied limit (N),
4 * a value greater than N if the string is longer than the limit, else
5 * strlen.
6 *
7 * Inputs:
8 *	in0:	address of buffer
9 *	in1:	string length limit N
10 * Outputs:
11 *	r8:	0 in case of fault, strlen(buffer)+1 otherwise
12 *
13 * Copyright (C) 1999, 2001 David Mosberger-Tang <davidm@hpl.hp.com>
14 */
15
16#include <asm/asmmacro.h>
17#include <asm/export.h>
18
19GLOBAL_ENTRY(__strnlen_user)
20	.prologue
21	alloc r2=ar.pfs,2,0,0,0
22	.save ar.lc, r16
23	mov r16=ar.lc			// preserve ar.lc
24
25	.body
26
27	add r3=-1,in1
28	;;
29	mov ar.lc=r3
30	mov r9=0
31	;;
32	// XXX braindead strlen loop---this needs to be optimized
33.Loop1:
34	EXCLR(.Lexit, ld1 r8=[in0],1)
35	add r9=1,r9
36	;;
37	cmp.eq p6,p0=r8,r0
38(p6)	br.cond.dpnt .Lexit
39	br.cloop.dptk.few .Loop1
40
41	add r9=1,in1			// NUL not found---return N+1
42	;;
43.Lexit:
44	mov r8=r9
45	mov ar.lc=r16			// restore ar.lc
46	br.ret.sptk.many rp
47END(__strnlen_user)
48EXPORT_SYMBOL(__strnlen_user)
49