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authorMike Frysinger <vapier@gentoo.org>2005-08-26 00:01:54 +0000
committerMike Frysinger <vapier@gentoo.org>2005-08-26 00:01:54 +0000
commitd71ff82e7019e91ae9f76af391e7f677d421e205 (patch)
treeb28b78dd5619b59cd28d11f007543e69fbe4bf12 /libc/string/sparc/sparc32/strlen.S
parentb11c2a4d0b7cf8095b93ae70fc187f0feadae5a1 (diff)
import sparc-optimized string functions from glibc
Diffstat (limited to 'libc/string/sparc/sparc32/strlen.S')
-rw-r--r--libc/string/sparc/sparc32/strlen.S101
1 files changed, 101 insertions, 0 deletions
diff --git a/libc/string/sparc/sparc32/strlen.S b/libc/string/sparc/sparc32/strlen.S
new file mode 100644
index 000000000..cc455ac89
--- /dev/null
+++ b/libc/string/sparc/sparc32/strlen.S
@@ -0,0 +1,101 @@
+/* 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)