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/* Copyright (C) 1996-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson (rth@tamu.edu)
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. Return the address of the terminating null in DEST, if
any, else DEST + COUNT. */
#include <sysdep.h>
.set noat
.set noreorder
.text
ENTRY(__stpncpy)
ldgp gp, 0(pv)
#ifdef PROF
lda AT, _mcount
jsr AT, (AT), _mcount
#endif
.prologue 1
beq a2, $zerocount
jsr t9, __stxncpy # do the work of the copy
and t8, 0xf0, t3 # binary search for byte offset of the
and t8, 0xcc, t2 # last byte written.
and t8, 0xaa, t1
andnot a0, 7, v0
cmovne t3, 4, t3
cmovne t2, 2, t2
cmovne t1, 1, t1
addq v0, t3, v0
addq t1, t2, t1
addq v0, t1, v0
bne a2, $multiword # do we have full words left?
.align 3
zapnot t0, t8, t4 # e0 : was last byte a null?
subq t8, 1, t2 # .. e1 :
addq v0, 1, t5 # e0 :
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
cmovne t4, t5, v0 # .. e1 : if last written wasnt null, inc v0
zap t0, t3, t0 # e0 :
stq_u t0, 0(a0) # e1 :
ret # .. e1 :
.align 3
$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 :
ret # .. e1 :
$zerocount:
mov a0, v0
ret
END(__stpncpy)
libc_hidden_def (__stpncpy)
weak_alias (__stpncpy, stpncpy)
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