diff options
Diffstat (limited to 'sysdeps/sparc/sparc32/strlen.S')
| -rw-r--r-- | sysdeps/sparc/sparc32/strlen.S | 128 |
1 files changed, 49 insertions, 79 deletions
diff --git a/sysdeps/sparc/sparc32/strlen.S b/sysdeps/sparc/sparc32/strlen.S index ed92f20e28..2945bb5484 100644 --- a/sysdeps/sparc/sparc32/strlen.S +++ b/sysdeps/sparc/sparc32/strlen.S @@ -1,8 +1,9 @@ /* Determine the length of a string. For SPARC v7. - Copyright (C) 1996, 1999, 2003 Free Software Foundation, Inc. + Copyright (C) 1996, 1999, 2003, 2010 Free Software Foundation, Inc. This file is part of the GNU C Library. - Contributed by Jakub Jelinek <jj@ultra.linux.cz>. + Contributed by Jakub Jelinek <jj@ultra.linux.cz> and + David S. Miller <davem@davemloft.net>. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public @@ -21,86 +22,55 @@ #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 ENTRY(strlen) - mov %o0, %o1 - andcc %o0, 3, %g0 - be 20f - sethi %hi(0x80808080), %o4 - - ldub [%o0], %o5 - cmp %o5, 0 - be 21f - add %o0, 1, %o0 - andcc %o0, 3, %g0 - be 4f - or %o4, %lo(0x80808080), %o3 - ldub [%o0], %o5 - cmp %o5, 0 - be 22f - add %o0, 1, %o0 - andcc %o0, 3, %g0 - be 5f - sethi %hi(0x01010101), %o4 - ldub [%o0], %o5 - cmp %o5, 0 - be 23f - add %o0, 1, %o0 - b 11f - or %o4, %lo(0x01010101), %o2 -21: retl - mov 0, %o0 -22: retl - mov 1, %o0 -23: retl - mov 2, %o0 - -20: 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 + mov %o0, %o1 + andn %o0, 0x3, %o0 + + ld [%o0], %o5 + and %o1, 0x3, %g1 + mov -1, %g5 + + sethi %hi(0x01010101), %o2 + sll %g1, 3, %g1 + + or %o2, %lo(0x01010101), %o2 + srl %g5, %g1, %g2 + + orn %o5, %g2, %o5 + sll %o2, 7, %o3 +10: add %o0, 4, %o0 + + andn %o3, %o5, %g1 + sub %o5, %o2, %g2 + + andcc %g1, %g2, %g0 + be,a 10b + ld [%o0], %o5 + + srl %o5, 24, %g1 + + andcc %g1, 0xff, %g0 + be 90f + sub %o0, 4, %o0 + + srl %o5, 16, %g2 + + andcc %g2, 0xff, %g0 + be 90f + add %o0, 1, %o0 + + srl %o5, 8, %g1 + + andcc %g1, 0xff, %g0 + be 90f + add %o0, 1, %o0 + + add %o0, 1, %o0 + +90: retl + sub %o0, %o1, %o0 END(strlen) libc_hidden_builtin_def (strlen) |