/* Copyright (C) 2000-2018 Free Software Foundation, Inc.

   EV67 optimized by Rick Gorton <rick.gorton@alpha-processor.com>.

   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.  */

#include <sysdep.h>

	.arch ev6

	.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, t2	# E : 00000000000000ch

	insbl	a1, 1, t4	# U : 000000000000ch00

	insbl	a1, 2, t5	# U : 0000000000ch0000

	ldq_u   t0, 0(a0)	# L : load first quadword Latency=3

	mov	zero, t6	# E : t6 is last match aligned addr

	or	t2, t4, a1	# E : 000000000000chch

	sll	t5, 8, t3	# U : 00000000ch000000

	mov	zero, t8	# E : t8 is last match byte compare mask

	andnot  a0, 7, v0	# E : align source addr

	or	t5, t3, t3	# E : 00000000chch0000

	sll	a1, 32, t2	# U : 0000chch00000000

	sll	a1, 48, t4	# U : chch000000000000

	or	t4, a1, a1	# E : chch00000000chch

	or	t2, t3, t2	# E : 0000chchchch0000

	or	a1, t2, a1	# E : chchchchchchchch

	lda	t5, -1		# E : build garbage mask

	cmpbge  zero, t0, t1	# E : bits set iff byte == zero

	mskqh	t5, a0, t4	# E : Complete garbage mask

	xor	t0, a1, t2	# E : make bytes == c zero

	cmpbge	zero, t4, t4	# E : bits set iff byte is garbage

	cmpbge  zero, t2, t3	# E : bits set iff byte == c

	andnot	t1, t4, t1	# E : clear garbage from null test

	andnot	t3, t4, t3	# E : clear garbage from char test

	bne	t1, $eos	# U : did we already hit the terminator?

	/* Character search main loop */

$loop:

	ldq	t0, 8(v0)	# L : load next quadword

	cmovne	t3, v0, t6	# E : save previous comparisons match

	nop			#   : Latency=2, extra map slot (keep nop with cmov)

	nop

	cmovne	t3, t3, t8	# E : Latency=2, extra map slot

	nop			#   : keep with cmovne

	addq	v0, 8, v0	# E :

	xor	t0, a1, t2	# E :

	cmpbge	zero, t0, t1	# E : bits set iff byte == zero

	cmpbge	zero, t2, t3	# E : bits set iff byte == c

	beq	t1, $loop	# U : if we havnt seen a null, loop

	nop

	/* Mask out character matches after terminator */

$eos:

	negq	t1, t4		# E : isolate first null byte match

	and	t1, t4, t4	# E :

	subq	t4, 1, t5	# E : build a mask of the bytes upto...

	or	t4, t5, t4	# E : ... and including the null

	and	t3, t4, t3	# E : mask out char matches after null

	cmovne	t3, t3, t8	# E : save it, if match found Latency=2, extra map slot

	nop			#   : Keep with cmovne

	nop

	cmovne	t3, v0, t6	# E :

	nop			#   : Keep with cmovne

	/* Locate the address of the last matched character */

	ctlz	t8, t2		# U0 : Latency=3 (0x40 for t8=0)

	nop

	cmoveq	t8, 0x3f, t2	# E : Compensate for case when no match is seen

	nop			# E : hide the cmov latency (2) behind ctlz latency

	lda	t5, 0x3f($31)	# E :

	subq	t5, t2, t5	# E : Normalize leading zero count

	addq	t6, t5, v0	# E : and add to quadword address

	ret			# L0 : Latency=3

	nop

	nop

END(strrchr)

weak_alias (strrchr, rindex)

libc_hidden_builtin_def (strrchr)