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/* Optimized strcpy for Xtensa.
Copyright (C) 2001, 2007 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, write to the Free
Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
Boston, MA 02110-1301, USA. */
#include <sysdep.h>
#include <bits/xtensa-config.h>
#ifdef __XTENSA_EB__
#define MASK0 0xff000000
#define MASK1 0x00ff0000
#define MASK2 0x0000ff00
#define MASK3 0x000000ff
#else
#define MASK0 0x000000ff
#define MASK1 0x0000ff00
#define MASK2 0x00ff0000
#define MASK3 0xff000000
#endif
/* Do not use .literal_position in the ENTRY macro. */
#undef LITERAL_POSITION
#define LITERAL_POSITION
.text
.align 4
.literal_position
__strncpy_aux:
.Lsrc1mod2: /* src address is odd */
l8ui a8, a3, 0 /* get byte 0 */
addi a3, a3, 1 /* advance src pointer */
s8i a8, a10, 0 /* store byte 0 */
addi a4, a4, -1 /* decrement n */
beqz a4, .Lret /* if n is zero */
addi a10, a10, 1 /* advance dst pointer */
beqz a8, .Lfill /* if byte 0 is zero */
bbci.l a3, 1, .Lsrcaligned /* if src is now word-aligned */
.Lsrc2mod4: /* src address is 2 mod 4 */
l8ui a8, a3, 0 /* get byte 0 */
addi a4, a4, -1 /* decrement n */
s8i a8, a10, 0 /* store byte 0 */
beqz a4, .Lret /* if n is zero */
addi a10, a10, 1 /* advance dst pointer */
beqz a8, .Lfill /* if byte 0 is zero */
l8ui a8, a3, 1 /* get byte 0 */
addi a3, a3, 2 /* advance src pointer */
s8i a8, a10, 0 /* store byte 0 */
addi a4, a4, -1 /* decrement n */
beqz a4, .Lret /* if n is zero */
addi a10, a10, 1 /* advance dst pointer */
bnez a8, .Lsrcaligned
j .Lfill
.Lret:
retw
ENTRY (strncpy)
/* a2 = dst, a3 = src */
mov a10, a2 /* leave dst in return value register */
beqz a4, .Lret /* if n is zero */
movi a11, MASK0
movi a5, MASK1
movi a6, MASK2
movi a7, MASK3
bbsi.l a3, 0, .Lsrc1mod2
bbsi.l a3, 1, .Lsrc2mod4
.Lsrcaligned:
/* Check if the destination is aligned. */
movi a8, 3
bnone a10, a8, .Laligned
j .Ldstunaligned
/* Fill the dst with zeros -- n is at least 1. */
.Lfill:
movi a9, 0
bbsi.l a10, 0, .Lfill1mod2
bbsi.l a10, 1, .Lfill2mod4
.Lfillaligned:
blti a4, 4, .Lfillcleanup
/* Loop filling complete words with zero. */
#if XCHAL_HAVE_LOOPS
srai a8, a4, 2
loop a8, 1f
s32i a9, a10, 0
addi a10, a10, 4
1: slli a8, a8, 2
sub a4, a4, a8
#else /* !XCHAL_HAVE_LOOPS */
1: s32i a9, a10, 0
addi a10, a10, 4
addi a4, a4, -4
bgei a4, 4, 1b
#endif /* !XCHAL_HAVE_LOOPS */
beqz a4, 2f
.Lfillcleanup:
/* Fill leftover (1 to 3) bytes with zero. */
s8i a9, a10, 0 /* store byte 0 */
addi a4, a4, -1 /* decrement n */
addi a10, a10, 1
bnez a4, .Lfillcleanup
2: retw
.Lfill1mod2: /* dst address is odd */
s8i a9, a10, 0 /* store byte 0 */
addi a4, a4, -1 /* decrement n */
beqz a4, 2b /* if n is zero */
addi a10, a10, 1 /* advance dst pointer */
bbci.l a10, 1, .Lfillaligned /* if dst is now word-aligned */
.Lfill2mod4: /* dst address is 2 mod 4 */
s8i a9, a10, 0 /* store byte 0 */
addi a4, a4, -1 /* decrement n */
beqz a4, 2b /* if n is zero */
s8i a9, a10, 1 /* store byte 1 */
addi a4, a4, -1 /* decrement n */
beqz a4, 2b /* if n is zero */
addi a10, a10, 2 /* advance dst pointer */
j .Lfillaligned
/* dst is word-aligned; src is word-aligned; n is at least 1. */
.align 4
/* (2 mod 4) alignment for loop instruction */
.Laligned:
#if XCHAL_HAVE_LOOPS
_movi.n a8, 0 /* set up for the maximum loop count */
loop a8, 1f /* loop forever (almost anyway) */
blti a4, 5, .Ldstunaligned /* n is near limit; do one at a time */
l32i a8, a3, 0 /* get word from src */
addi a3, a3, 4 /* advance src pointer */
bnone a8, a11, .Lz0 /* if byte 0 is zero */
bnone a8, a5, .Lz1 /* if byte 1 is zero */
bnone a8, a6, .Lz2 /* if byte 2 is zero */
s32i a8, a10, 0 /* store word to dst */
addi a4, a4, -4 /* decrement n */
addi a10, a10, 4 /* advance dst pointer */
bnone a8, a7, .Lfill /* if byte 3 is zero */
1:
#else /* !XCHAL_HAVE_LOOPS */
1: blti a4, 5, .Ldstunaligned /* n is near limit; do one at a time */
l32i a8, a3, 0 /* get word from src */
addi a3, a3, 4 /* advance src pointer */
bnone a8, a11, .Lz0 /* if byte 0 is zero */
bnone a8, a5, .Lz1 /* if byte 1 is zero */
bnone a8, a6, .Lz2 /* if byte 2 is zero */
s32i a8, a10, 0 /* store word to dst */
addi a4, a4, -4 /* decrement n */
addi a10, a10, 4 /* advance dst pointer */
bany a8, a7, 1b /* no zeroes */
#endif /* !XCHAL_HAVE_LOOPS */
j .Lfill
.Lz0: /* Byte 0 is zero. */
#ifdef __XTENSA_EB__
movi a8, 0
#endif
s8i a8, a10, 0
addi a4, a4, -1 /* decrement n */
addi a10, a10, 1 /* advance dst pointer */
j .Lfill
.Lz1: /* Byte 1 is zero. */
#ifdef __XTENSA_EB__
extui a8, a8, 16, 16
#endif
s16i a8, a10, 0
addi a4, a4, -2 /* decrement n */
addi a10, a10, 2 /* advance dst pointer */
j .Lfill
.Lz2: /* Byte 2 is zero. */
#ifdef __XTENSA_EB__
extui a8, a8, 16, 16
#endif
s16i a8, a10, 0
movi a8, 0
s8i a8, a10, 2
addi a4, a4, -3 /* decrement n */
addi a10, a10, 3 /* advance dst pointer */
j .Lfill
.align 4
/* (2 mod 4) alignment for loop instruction */
.Ldstunaligned:
#if XCHAL_HAVE_LOOPS
_movi.n a8, 0 /* set up for the maximum loop count */
loop a8, 2f /* loop forever (almost anyway) */
#endif
1: l8ui a8, a3, 0
addi a3, a3, 1
s8i a8, a10, 0
addi a4, a4, -1
beqz a4, 3f
addi a10, a10, 1
#if XCHAL_HAVE_LOOPS
beqz a8, 2f
#else
bnez a8, 1b
#endif
2: j .Lfill
3: retw
libc_hidden_def (strncpy)
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