[src/trunk]: src/lib/libc/arch/arm/string Add simple version of strncat for ARM.

[matt <matt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/edf2bf78c7ed
branches:  trunk
changeset: 784249:edf2bf78c7ed
user:      matt <matt%NetBSD.org@localhost>
date:      Wed Jan 23 05:44:52 2013 +0000

description:
Add simple version of strncat for ARM.

diffstat:

 lib/libc/arch/arm/string/strncat_naive.S |  53 ++++++++++++++++++++++++++++++++
 1 files changed, 53 insertions(+), 0 deletions(-)

diffs (57 lines):

diff -r ed09ec35ce5b -r edf2bf78c7ed lib/libc/arch/arm/string/strncat_naive.S
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/libc/arch/arm/string/strncat_naive.S  Wed Jan 23 05:44:52 2013 +0000
@@ -0,0 +1,53 @@
+/*-
+ * Copyright (c) 2013 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Matt Thomas of 3am Software Foundry.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+
+RCSID("$NetBSD: strncat_naive.S,v 1.1 2013/01/23 05:44:52 matt Exp $")
+
+/* LINTSTUB: char *strncat(char *, const char *, size_t) */
+ENTRY(strncat)
+       teq     r2, #0                  /* count is 0? */
+       RETc(eq)                        /*   yes, just return dst */
+       mov     ip, r0                  /* need to preserve r0 */
+1:     ldrb    r3, [ip], #1            /* load next byte */
+       teq     r3, #0                  /* was it a NUL? */
+       bne     1b                      /*   no, get next byte */
+       sub     ip, ip, #1              /* back up one to the NUL */
+2:     subs    r2, r2, #1              /* subtract 1 from the count */
+       blt     3f                      /*   <0? write terminating NUL */
+       ldrb    r3, [r1], #1            /* load next byte from append */
+       strb    r3, [ip], #1            /* store it */
+       teq     r3, #0                  /* was it a NUL? */
+       bne     2b                      /*   no, get next byte */
+       RET                             /* return */
+3:     mov     r3, #0                  /* load a NUL */
+       strb    r3, [ip]                /* store it */
+       RET                             /* return */
+END(strncat)