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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Returns 0 if exception before NUL or reaching the supplied limit (N),
3 * a value greater than N if the string is longer than the limit, else
4 * strlen.
5 *
6 * Inputs:
7 * in0: address of buffer
8 * in1: string length limit N
9 * Outputs:
10 * r8: 0 in case of fault, strlen(buffer)+1 otherwise
11 *
12 * Copyright (C) 1999, 2001 David Mosberger-Tang <davidm@hpl.hp.com>
13 */
14
15#include <asm/asmmacro.h>
16
17GLOBAL_ENTRY(__strnlen_user)
18 .prologue
19 alloc r2=ar.pfs,2,0,0,0
20 .save ar.lc, r16
21 mov r16=ar.lc // preserve ar.lc
22
23 .body
24
25 add r3=-1,in1
26 ;;
27 mov ar.lc=r3
28 mov r9=0
29 ;;
30 // XXX braindead strlen loop---this needs to be optimized
31.Loop1:
32 EXCLR(.Lexit, ld1 r8=[in0],1)
33 add r9=1,r9
34 ;;
35 cmp.eq p6,p0=r8,r0
36(p6) br.cond.dpnt .Lexit
37 br.cloop.dptk.few .Loop1
38
39 add r9=1,in1 // NUL not found---return N+1
40 ;;
41.Lexit:
42 mov r8=r9
43 mov ar.lc=r16 // restore ar.lc
44 br.ret.sptk.many rp
45END(__strnlen_user)