Blame sysdeps/alpha/strcat.S

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/* Copyright (C) 1996-2018 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   Contributed by Richard Henderson <rth@tamu.edu>, 1996.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library.  If not, see
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   <http://www.gnu.org/licenses/>.  */
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/* Append a null-terminated string from SRC to DST.  */
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#include <sysdep.h>
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	.text
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ENTRY(strcat)
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	ldgp	gp, 0(pv)
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#ifdef PROF
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	.set noat
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	lda	AT, _mcount
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	jsr	AT, (AT), _mcount
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	.set at
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#endif
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	.prologue 1
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	mov	a0, v0		# set up return value
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	/* Find the end of the string.  */
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	ldq_u   t0, 0(a0)	# load first quadword (a0 may be misaligned)
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	lda     t1, -1(zero)
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	insqh   t1, a0, t1
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	andnot  a0, 7, a0
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	or      t1, t0, t0
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	cmpbge  zero, t0, t1	# t1 <- bitmask: bit i == 1 <==> i-th byte == 0
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	bne     t1, $found
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$loop:	ldq     t0, 8(a0)
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	addq    a0, 8, a0	# addr += 8
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	cmpbge  zero, t0, t1
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	beq     t1, $loop
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$found:	negq    t1, t2		# clear all but least set bit
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	and     t1, t2, t1
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	and     t1, 0xf0, t2	# binary search for that set bit
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	and	t1, 0xcc, t3
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	and	t1, 0xaa, t4
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	cmovne	t2, 4, t2
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	cmovne	t3, 2, t3
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	cmovne	t4, 1, t4
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	addq	t2, t3, t2
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	addq	a0, t4, a0
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	addq	a0, t2, a0
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	/* Now do the append.  */
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	mov	ra, t9
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	jmp	$31, __stxcpy
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	END(strcat)
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libc_hidden_builtin_def (strcat)