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glibc/sysdeps/sparc/sparc32/stpcpy.S
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/* Copy SRC to DEST returning the address of the terminating '\0' in DEST. | |
For SPARC v7. | |
Copyright (C) 1996, 1999, 2002, 2004 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Jakub Jelinek <jj@ultra.linux.cz>. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 of the License, or (at your option) any later version. | |
The GNU C Library is distributed in the hope that it will be useful, | |
but WITHOUT ANY WARRANTY; without even the implied warranty of | |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, write to the Free | |
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
02111-1307 USA. */ | |
#include <sysdep.h> | |
/* Normally, this uses ((xword - 0x01010101) & 0x80808080) test | |
to find out if any byte in xword could be zero. This is fast, but | |
also gives false alarm for any byte in range 0x81-0xff. It does | |
not matter for correctness, as if this test tells us there could | |
be some zero byte, we check it byte by byte, but if bytes with | |
high bits set are common in the strings, then this will give poor | |
performance. You can #define EIGHTBIT_NOT_RARE and the algorithm | |
will use one tick slower, but more precise test | |
((xword - 0x01010101) & (~xword) & 0x80808080), | |
which does not give any false alarms (but if some bits are set, | |
one cannot assume from it which bytes are zero and which are not). | |
It is yet to be measured, what is the correct default for glibc | |
in these days for an average user. | |
*/ | |
.text | |
.align 4 | |
10: ldub [%o1], %o5 | |
stb %o5, [%o0] | |
cmp %o5, 0 | |
add %o0, 1, %o0 | |
be 1f | |
add %o1, 1, %o1 | |
andcc %o1, 3, %g0 | |
be 4f | |
or %o4, %lo(0x80808080), %o3 | |
ldub [%o1], %o5 | |
stb %o5, [%o0] | |
cmp %o5, 0 | |
add %o0, 1, %o0 | |
be 1f | |
add %o1, 1, %o1 | |
andcc %o1, 3, %g0 | |
be 5f | |
sethi %hi(0x01010101), %o4 | |
ldub [%o1], %o5 | |
stb %o5, [%o0] | |
cmp %o5, 0 | |
add %o0, 1, %o0 | |
be 1f | |
add %o1, 1, %o1 | |
b 6f | |
or %o4, %lo(0x01010101), %o2 | |
1: retl | |
add %o0, -1, %o0 | |
ENTRY(__stpcpy) | |
andcc %o1, 3, %g0 | |
bne 10b | |
sethi %hi(0x80808080), %o4 | |
or %o4, %lo(0x80808080), %o3 | |
4: sethi %hi(0x01010101), %o4 | |
5: or %o4, %lo(0x01010101), %o2 | |
6: andcc %o0, 3, %g0 | |
bne 16f | |
sub %g0, 4, %g1 | |
11: add %g1, 4, %g1 | |
ld [%o1 + %g1], %o5 | |
sub %o5, %o2, %o4 | |
#ifdef EIGHTBIT_NOT_RARE | |
andn %o4, %o5, %o4 | |
#endif | |
andcc %o4, %o3, %g0 | |
be,a 11b | |
st %o5, [%o0 + %g1] | |
/* Check every byte. */ | |
srl %o5, 24, %g5 | |
andcc %g5, 0xff, %g0 | |
be 14f | |
srl %o5, 16, %g5 | |
andcc %g5, 0xff, %g0 | |
be 13f | |
srl %o5, 8, %g5 | |
andcc %g5, 0xff, %g0 | |
be 12f | |
andcc %o5, 0xff, %g0 | |
bne 11b | |
st %o5, [%o0 + %g1] | |
add %o0, %g1, %o0 | |
retl | |
add %o0, 3, %o0 | |
12: srl %o5, 16, %o5 | |
sth %o5, [%o0 + %g1] | |
add %g1, 2, %g1 | |
stb %g0, [%o0 + %g1] | |
retl | |
add %o0, %g1, %o0 | |
13: srl %o5, 16, %o5 | |
sth %o5, [%o0 + %g1] | |
add %g1, 1, %g1 | |
retl | |
add %o0, %g1, %o0 | |
14: stb %g0, [%o0 + %g1] | |
retl | |
add %o0, %g1, %o0 | |
15: srl %o5, 24, %o4 | |
srl %o5, 16, %g1 | |
stb %o4, [%o0] | |
srl %o5, 8, %g4 | |
stb %g1, [%o0 + 1] | |
stb %g4, [%o0 + 2] | |
stb %o5, [%o0 + 3] | |
add %o0, 4, %o0 | |
16: ld [%o1], %o5 | |
sub %o5, %o2, %o4 | |
andcc %o4, %o3, %g0 | |
be 15b | |
add %o1, 4, %o1 | |
/* Check every byte. */ | |
srl %o5, 24, %g5 | |
andcc %g5, 0xff, %g4 | |
be 19f | |
stb %g4, [%o0] | |
srl %o5, 16, %g5 | |
andcc %g5, 0xff, %g4 | |
be 18f | |
stb %g4, [%o0 + 1] | |
srl %o5, 8, %g5 | |
andcc %g5, 0xff, %g4 | |
be 17f | |
stb %g4, [%o0 + 2] | |
andcc %o5, 0xff, %g4 | |
stb %g4, [%o0 + 3] | |
bne 16b | |
add %o0, 4, %o0 | |
retl | |
sub %o0, 1, %o0 | |
17: retl | |
add %o0, 2, %o0 | |
18: retl | |
add %o0, 1, %o0 | |
19: retl | |
nop | |
END(__stpcpy) | |
weak_alias (__stpcpy, stpcpy) | |
libc_hidden_def (__stpcpy) | |
libc_hidden_builtin_def (stpcpy) |