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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)