/* 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)