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authorRichard Henderson <rth@twiddle.net>2014-02-12 06:54:57 -0800
committerRichard Henderson <rth@twiddle.net>2014-02-12 07:00:06 -0800
commit68b7efaadb1b6045a56277ea62d324c20ac0b633 (patch)
tree07b51c9866373430373fb90b252d46c23cc1707e /sysdeps/alpha/strrchr.S
parent8fd7b0d5591e59ed5cb3078b351bd49314a66cef (diff)
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Relocate alpha from ports to libc
Also fixed the following whitespace nits to satisfy the push: sysdeps/alpha/alphaev6/memset.S:142: space before tab in indent. sysdeps/alpha/configure:1: new blank line at EOF. sysdeps/alpha/fpu/e_sqrt.c:126: space before tab in indent. sysdeps/alpha/preconfigure:1: new blank line at EOF. sysdeps/unix/sysv/linux/alpha/syscalls.list:1: new blank line at EOF.
Diffstat (limited to 'sysdeps/alpha/strrchr.S')
-rw-r--r--sysdeps/alpha/strrchr.S110
1 files changed, 110 insertions, 0 deletions
diff --git a/sysdeps/alpha/strrchr.S b/sysdeps/alpha/strrchr.S
new file mode 100644
index 0000000000..e85f0cf464
--- /dev/null
+++ b/sysdeps/alpha/strrchr.S
@@ -0,0 +1,110 @@
+/* Copyright (C) 1996-2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ 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/>. */
+
+/* Return the address of the last occurrence of a given character
+ within a null-terminated string, or null if it is not found.
+
+ This is generally scheduled for the EV5 (got to look out for my own
+ interests :-), but with EV4 needs in mind. There are, in fact, fewer
+ stalls on the EV4 than there are on the EV5.
+*/
+
+#include <sysdep.h>
+
+ .set noreorder
+ .set noat
+
+ENTRY(strrchr)
+#ifdef PROF
+ ldgp gp, 0(pv)
+ lda AT, _mcount
+ jsr AT, (AT), _mcount
+ .prologue 1
+#else
+ .prologue 0
+#endif
+
+ and a1, 0xff, a1 # e0 : zero extend our test character
+ mov zero, t6 # .. e1 : t6 is last match aligned addr
+ sll a1, 8, t5 # e0 : replicate our test character
+ mov zero, t7 # .. e1 : t7 is last match byte compare mask
+ or t5, a1, a1 # e0 :
+ ldq_u t0, 0(a0) # .. e1 : load first quadword
+ sll a1, 16, t5 # e0 :
+ andnot a0, 7, v0 # .. e1 : align source addr
+ or t5, a1, a1 # e0 :
+ lda t4, -1 # .. e1 : build garbage mask
+ sll a1, 32, t5 # e0 :
+ cmpbge zero, t0, t1 # .. e1 : bits set iff byte == zero
+ mskqh t4, a0, t4 # e0 :
+ or t5, a1, a1 # .. e1 : character replication complete
+ xor t0, a1, t2 # e0 : make bytes == c zero
+ cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage
+ cmpbge zero, t2, t3 # e0 : bits set iff byte == c
+ andnot t1, t4, t1 # .. e1 : clear garbage from null test
+ andnot t3, t4, t3 # e0 : clear garbage from char test
+ bne t1, $eos # .. e1 : did we already hit the terminator?
+
+ /* Character search main loop */
+$loop:
+ ldq t0, 8(v0) # e0 : load next quadword
+ cmovne t3, v0, t6 # .. e1 : save previous comparisons match
+ cmovne t3, t3, t7 # e0 :
+ addq v0, 8, v0 # .. e1 :
+ xor t0, a1, t2 # e0 :
+ cmpbge zero, t0, t1 # .. e1 : bits set iff byte == zero
+ cmpbge zero, t2, t3 # e0 : bits set iff byte == c
+ beq t1, $loop # .. e1 : if we havnt seen a null, loop
+
+ /* Mask out character matches after terminator */
+$eos:
+ negq t1, t4 # e0 : isolate first null byte match
+ and t1, t4, t4 # e1 :
+ subq t4, 1, t5 # e0 : build a mask of the bytes upto...
+ or t4, t5, t4 # e1 : ... and including the null
+
+ and t3, t4, t3 # e0 : mask out char matches after null
+ cmovne t3, t3, t7 # .. e1 : save it, if match found
+ cmovne t3, v0, t6 # e0 :
+
+ /* Locate the address of the last matched character */
+
+ /* Retain the early exit for the ev4 -- the ev5 mispredict penalty
+ is 5 cycles -- the same as just falling through. */
+ beq t7, $retnull # .. e1 :
+
+ and t7, 0xf0, t2 # e0 : binary search for the high bit set
+ cmovne t2, t2, t7 # .. e1 (zdb)
+ cmovne t2, 4, t2 # e0 :
+ and t7, 0xcc, t1 # .. e1 :
+ cmovne t1, t1, t7 # e0 :
+ cmovne t1, 2, t1 # .. e1 :
+ and t7, 0xaa, t0 # e0 :
+ cmovne t0, 1, t0 # .. e1 (zdb)
+ addq t2, t1, t1 # e0 :
+ addq t6, t0, v0 # .. e1 : add our aligned base ptr to the mix
+ addq v0, t1, v0 # e0 :
+ ret # .. e1 :
+
+$retnull:
+ mov zero, v0 # e0 :
+ ret # .. e1 :
+
+ END(strrchr)
+
+weak_alias (strrchr, rindex)
+libc_hidden_builtin_def (strrchr)