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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 "../../sysdeps/linux/xtensa/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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