| /* Determine the length of a string. |
| For SPARC v7. |
| Copyright (C) 1996, 1999, 2003 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. */ |
| |
| /* 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 [%o0], %o5 |
| cmp %o5, 0 |
| be 1f |
| add %o0, 1, %o0 |
| andcc %o0, 3, %g0 |
| be 4f |
| or %o4, %lo(0x80808080), %o3 |
| ldub [%o0], %o5 |
| cmp %o5, 0 |
| be 2f |
| add %o0, 1, %o0 |
| andcc %o0, 3, %g0 |
| be 5f |
| sethi %hi(0x01010101), %o4 |
| ldub [%o0], %o5 |
| cmp %o5, 0 |
| be 3f |
| add %o0, 1, %o0 |
| b 11f |
| or %o4, %lo(0x01010101), %o2 |
| 1: retl |
| mov 0, %o0 |
| 2: retl |
| mov 1, %o0 |
| 3: retl |
| mov 2, %o0 |
| |
| ENTRY(strlen) |
| mov %o0, %o1 |
| andcc %o0, 3, %g0 |
| bne 10b |
| sethi %hi(0x80808080), %o4 |
| or %o4, %lo(0x80808080), %o3 |
| 4: sethi %hi(0x01010101), %o4 |
| 5: or %o4, %lo(0x01010101), %o2 |
| 11: ld [%o0], %o5 |
| 12: sub %o5, %o2, %o4 |
| #ifdef EIGHTBIT_NOT_RARE |
| andn %o4, %o5, %o4 |
| #endif |
| andcc %o4, %o3, %g0 |
| be 11b |
| add %o0, 4, %o0 |
| |
| srl %o5, 24, %g5 |
| andcc %g5, 0xff, %g0 |
| be 13f |
| add %o0, -4, %o4 |
| srl %o5, 16, %g5 |
| andcc %g5, 0xff, %g0 |
| be 13f |
| add %o4, 1, %o4 |
| srl %o5, 8, %g5 |
| andcc %g5, 0xff, %g0 |
| be 13f |
| add %o4, 1, %o4 |
| andcc %o5, 0xff, %g0 |
| bne,a 12b |
| ld [%o0], %o5 |
| add %o4, 1, %o4 |
| 13: retl |
| sub %o4, %o1, %o0 |
| END(strlen) |
| libc_hidden_def(strlen) |