diff options
Diffstat (limited to 'lib/libc/arm/string/strlen.S')
-rw-r--r-- | lib/libc/arm/string/strlen.S | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/lib/libc/arm/string/strlen.S b/lib/libc/arm/string/strlen.S new file mode 100644 index 0000000..378257d --- /dev/null +++ b/lib/libc/arm/string/strlen.S @@ -0,0 +1,78 @@ +/*- + * Copyright (c) 2005 Olivier Houchard + * All rights reserved. + * + * 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 AUTHOR 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 AUTHOR 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> +__FBSDID("$FreeBSD$"); + +ENTRY(strlen) + mov r1, #0 + /* Check that the pointer is aligned on 32 bits. */ + ands r3, r0, #3 + beq .Loop + sub r0, r0, r3 + ldr r2, [r0] + add r0, r0, #4 + cmp r3, #2 + blt .Ldo_3 + bgt .Ldo_1 + /* So that the N bit is set. */ + cmp r3, #0 + b .Ldo_2 + +.Loop: + ldr r2, [r0] + add r0, r0, #4 +#ifndef __ARMEB__ + ands r3, r2, #0x000000ff +#else + ands r3, r2, #0xff000000 +#endif + addne r1, r1, #1 +.Ldo_3: +#ifndef __ARMEB__ + andnes r3, r2, #0x0000ff00 +#else + andnes r3, r2, #0x00ff0000 +#endif + addne r1, r1, #1 +.Ldo_2: +#ifndef __ARMEB__ + andnes r3, r2, #0x00ff0000 +#else + andnes r3, r2, #0x0000ff00 +#endif + addne r1, r1, #1 +.Ldo_1: +#ifndef __ARMEB__ + andnes r3, r2, #0xff000000 +#else + andnes r3, r2, #0x000000ff +#endif + addne r1, r1, #1 + bne .Loop +.Lexit: + mov r0, r1 + RET |