linux/arch/sparc/lib/strlen.S
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

81 lines
1.3 KiB
ArmAsm

/* strlen.S: Sparc optimized strlen code
* Hand optimized from GNU libc's strlen
* Copyright (C) 1991,1996 Free Software Foundation
* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
*/
#define LO_MAGIC 0x01010101
#define HI_MAGIC 0x80808080
0:
ldub [%o0], %o5
cmp %o5, 0
be 1f
add %o0, 1, %o0
andcc %o0, 3, %g0
be 4f
or %o4, %lo(HI_MAGIC), %o3
ldub [%o0], %o5
cmp %o5, 0
be 2f
add %o0, 1, %o0
andcc %o0, 3, %g0
be 5f
sethi %hi(LO_MAGIC), %o4
ldub [%o0], %o5
cmp %o5, 0
be 3f
add %o0, 1, %o0
b 8f
or %o4, %lo(LO_MAGIC), %o2
1:
retl
mov 0, %o0
2:
retl
mov 1, %o0
3:
retl
mov 2, %o0
.align 4
.global strlen
strlen:
mov %o0, %o1
andcc %o0, 3, %g0
bne 0b
sethi %hi(HI_MAGIC), %o4
or %o4, %lo(HI_MAGIC), %o3
4:
sethi %hi(LO_MAGIC), %o4
5:
or %o4, %lo(LO_MAGIC), %o2
8:
ld [%o0], %o5
2:
sub %o5, %o2, %o4
andcc %o4, %o3, %g0
be 8b
add %o0, 4, %o0
/* Check every byte. */
srl %o5, 24, %g5
andcc %g5, 0xff, %g0
be 1f
add %o0, -4, %o4
srl %o5, 16, %g5
andcc %g5, 0xff, %g0
be 1f
add %o4, 1, %o4
srl %o5, 8, %g5
andcc %g5, 0xff, %g0
be 1f
add %o4, 1, %o4
andcc %o5, 0xff, %g0
bne,a 2b
ld [%o0], %o5
add %o4, 1, %o4
1:
retl
sub %o4, %o1, %o0