import sparc-optimized string functions from glibc

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)