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authorMike Frysinger <vapier@gentoo.org>2006-02-04 01:20:54 +0000
committerMike Frysinger <vapier@gentoo.org>2006-02-04 01:20:54 +0000
commitc429bf3057c87dd9545fc2d824b5930c52f7dfb8 (patch)
treef207534c6a7a16795f8e7a099c1b48180e9db94f /libc/string/ia64/strlen.S
parent798669dc65077f81b6facd2415463a1bda13c4d7 (diff)
import files from glibc for an ia64/static port
Diffstat (limited to 'libc/string/ia64/strlen.S')
-rw-r--r--libc/string/ia64/strlen.S98
1 files changed, 98 insertions, 0 deletions
diff --git a/libc/string/ia64/strlen.S b/libc/string/ia64/strlen.S
new file mode 100644
index 000000000..f5a6ef044
--- /dev/null
+++ b/libc/string/ia64/strlen.S
@@ -0,0 +1,98 @@
+/* Optimized version of the standard strlen() function.
+ This file is part of the GNU C Library.
+ Copyright (C) 2000, 2001, 2003, 2005 Free Software Foundation, Inc.
+ Contributed by Dan Pop <Dan.Pop@cern.ch>.
+
+ 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. */
+
+/* Return: the length of the input string
+
+ Input:
+ in0: str
+
+ Look for the null character byte by byte, until we reach a word aligned
+ address, then search word by word, using the czx instruction. We're
+ also doing one word of read ahead, which could cause problems if the
+ null character is on the last word of a page and the next page is not
+ mapped in the process address space. Hence the use of the speculative
+ load.
+
+ This implementation assumes little endian mode. For big endian mode,
+ the instruction czx1.r should be replaced by czx1.l. */
+
+#include <sysdep.h>
+#undef ret
+
+#define saved_lc r18
+#define str r19
+#define pos0 r20
+#define val1 r21
+#define val2 r22
+#define origadd r23
+#define tmp r24
+#define loopcnt r30
+#define len ret0
+
+ENTRY(strlen)
+ .prologue
+ alloc r2 = ar.pfs, 1, 0, 0, 0
+ .save ar.lc, saved_lc
+ mov saved_lc = ar.lc // save the loop counter
+ .body
+ mov str = in0
+ mov len = r0 // len = 0
+ and tmp = 7, in0 // tmp = str % 8
+ ;;
+ sub loopcnt = 8, tmp // loopcnt = 8 - tmp
+ cmp.eq p6, p0 = tmp, r0
+(p6) br.cond.sptk .str_aligned;;
+ adds loopcnt = -1, loopcnt;;
+ mov ar.lc = loopcnt
+.l1:
+ ld1 val2 = [str], 1
+ ;;
+ cmp.eq p6, p0 = val2, r0
+(p6) br.cond.spnt .restore_and_exit
+ adds len = 1, len
+ br.cloop.dptk .l1
+.str_aligned:
+ mov origadd = str // origadd = orig
+ ld8 val1 = [str], 8;;
+ nop.b 0
+ nop.b 0
+.l2: ld8.s val2 = [str], 8 // don't bomb out here
+ czx1.r pos0 = val1
+ ;;
+ cmp.ne p6, p0 = 8, pos0
+(p6) br.cond.spnt .foundit
+ chk.s val2, .recovery
+.back:
+ mov val1 = val2
+ br.cond.dptk .l2
+.foundit:
+ sub tmp = str, origadd // tmp = crt address - orig
+ add len = len, pos0;;
+ add len = len, tmp;;
+ adds len = -16, len
+.restore_and_exit:
+ mov ar.lc = saved_lc // restore the loop counter
+ br.ret.sptk.many b0
+.recovery:
+ adds str = -8, str;;
+ ld8 val2 = [str], 8 // bomb out here
+ br.cond.sptk .back
+END(strlen)
+libc_hidden_def (strlen)