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/* Copyright (C) 1996-2021 Free Software Foundation, Inc.
Contributed by Richard Henderson (rth@tamu.edu)
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
<https://www.gnu.org/licenses/>. */
/* Copy no more than COUNT bytes of the null-terminated string from
SRC to DST. If SRC does not cover all of COUNT, the balance is
zeroed. */
#include <sysdep.h>
.set noat
.set noreorder
.text
ENTRY(strncpy)
ldgp gp, 0(pv)
#ifdef PROF
lda AT, _mcount
jsr AT, (AT), _mcount
#endif
.prologue 1
mov a0, v0 # set return value now
beq a2, $zerocount
jsr t9, __stxncpy # do the work of the copy
bne a2, $multiword # do we have full words left?
.align 3
subq t8, 1, t2 # e0 : guess not
subq t10, 1, t3 # .. e1 :
or t2, t8, t2 # e0 : clear the bits between the last
or t3, t10, t3 # .. e1 : written byte and the last byte in
andnot t3, t2, t3 # e0 : COUNT
zap t0, t3, t0 # e1 :
stq_u t0, 0(a0) # e0 :
ret # .. e1 :
$multiword:
subq t8, 1, t7 # e0 : clear the final bits in the prev
or t7, t8, t7 # e1 : word
zapnot t0, t7, t0 # e0 :
subq a2, 1, a2 # .. e1 :
stq_u t0, 0(a0) # e0 :
addq a0, 8, a0 # .. e1 :
beq a2, 1f # e1 :
blbc a2, 0f # e1 :
stq_u zero, 0(a0) # e0 : zero one word
subq a2, 1, a2 # .. e1 :
addq a0, 8, a0 # e0 :
beq a2, 1f # .. e1 :
0: stq_u zero, 0(a0) # e0 : zero two words
subq a2, 2, a2 # .. e1 :
stq_u zero, 8(a0) # e0 :
addq a0, 16, a0 # .. e1 :
bne a2, 0b # e1 :
unop
1: ldq_u t0, 0(a0) # e0 : clear the leading bits in the final
subq t10, 1, t7 # .. e1 : word
or t7, t10, t7 # e0 :
zap t0, t7, t0 # e1 (stall)
stq_u t0, 0(a0) # e0 :
$zerocount:
ret # .. e1 :
END(strncpy)
libc_hidden_builtin_def (strncpy)
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