Alpha ev67 rawmemchr implementation.

sysdeps/alpha/alphaev67/rawmemchr.S

@@ -0,0 +1,93 @@
+/* Copyright (C) 2000 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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+/* Return pointer to first occurrence of CH in STR.  */
+
+#include <sysdep.h>
+
+	.arch ev6
+	.set noreorder
+	.set noat
+
+ENTRY(__rawmemchr)
+#ifdef PROF
+	ldgp	gp, 0(pv)
+	lda	AT, _mcount
+	jsr	AT, (AT), _mcount
+	.prologue 1
+#else
+	.prologue 0
+#endif
+
+	ldq_u   t0, 0(a0)	# L : load first quadword Latency=3
+	and	a1, 0xff, t3	# E : 00000000000000ch
+	insbl	a1, 1, t5	# U : 000000000000ch00
+	insbl	a1, 7, a2	# U : ch00000000000000
+
+	insbl	t3, 6, a3	# U : 00ch000000000000
+	or	t5, t3, a1	# E : 000000000000chch
+	andnot  a0, 7, v0	# E : align our loop pointer
+	lda	t4, -1		# E : build garbage mask
+
+	mskqh	t4, a0, t4	# U : only want relevant part of first quad
+	or	a2, a3, a2	# E : chch000000000000
+	inswl	a1, 2, t5	# E : 00000000chch0000
+	inswl	a1, 4, a3	# E : 0000chch00000000
+
+	or	a1, a2, a1	# E : chch00000000chch
+	or	a3, t5, t5	# E : 0000chchchch0000
+	cmpbge	zero, t4, t4	# E : bits set iff byte is garbage
+	nop			# E :
+
+	/* This quad is _very_ serialized.  Lots of stalling happens */
+	or	t5, a1, a1	# E : chchchchchchchch
+	xor	t0, a1, t1	# E : make bytes == c zero
+	cmpbge  zero, t1, t0	# E : bits set iff byte == c
+	andnot	t0, t4, t0	# E : clear garbage bits
+
+	cttz	t0, a2		# U0 : speculative (in case we get a match)
+	nop			# E :
+	nop			# E :
+	bne	t0, $found	# U :
+
+	/*
+	 * Yuk.  This loop is going to stall like crazy waiting for the
+	 * data to be loaded.  Not much can be done about it unless it's
+	 * unrolled multiple times, which is generally unsafe.
+	 */
+$loop:
+	ldq	t0, 8(v0)	# L : Latency=3
+	addq	v0, 8, v0	# E :
+	xor	t0, a1, t1	# E :
+	cmpbge	zero, t1, t0	# E : bits set iff byte == c
+
+	cttz	t0, a2		# U0 : speculative (in case we get a match)
+	nop			# E :
+	nop			# E :
+	beq	t0, $loop	# U :
+
+$found:
+	negq    t0, t1		# E : clear all but least set bit
+	and     t0, t1, t0	# E :
+	addq	v0, a2, v0	# E : Add in the bit number from above
+	ret			# L0 :
+
+	END(__rawmemchr)
+
+weak_alias (__rawmemchr, rawmemchr)