/* 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, see <http://www.gnu.org/licenses/>. */ /* 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) libc_hidden_def(stpcpy)