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/* strncpy - copy at most n characters from a string from source to
destination. 64 bit S/390 version
Copyright (C) 2001-2018 Free Software Foundation, Inc.
Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
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
<http://www.gnu.org/licenses/>. */
/* INPUT PARAMETERS
%r2 = address of destination (dst)
%r3 = address of source (src)
%r4 = max of bytes to copy. */
#include "sysdep.h"
#include "asm-syntax.h"
ENTRY(strncpy)
.text
stg %r2,48(%r15) # save dst pointer
slgr %r2,%r3 # %r3 points to src, %r2+%r3 to dst
lghi %r1,7
ngr %r1,%r4 # last 3 bits of # bytes
srlg %r4,%r4,3
ltgr %r4,%r4 # less than 8 bytes to copy ?
jz .L1
bras %r5,.L0 # enter loop & load address of a 0
.long 0
.L0: icmh %r0,8,0(%r3) # first byte
jz .L3
icmh %r0,4,1(%r3) # second byte
jz .L4
icmh %r0,2,2(%r3) # third byte
jz .L5
icmh %r0,1,3(%r3) # fourth byte
jz .L6
icm %r0,8,4(%r3) # fifth byte
jz .L7
icm %r0,4,5(%r3) # sixth byte
jz .L8
icm %r0,2,6(%r3) # seventh byte
jz .L9
icm %r0,1,7(%r3) # eigth byte
jz .L10
stg %r0,0(%r2,%r3) # store all eight to dest.
la %r3,8(%r3)
brct %r4,.L0
.L1: ltgr %r1,%r1
jz .Lexit
.L2: icm %r0,1,0(%r3)
stc %r0,0(%r2,%r3)
la %r3,1(%r3)
jz .L11
brct %r1,.L2
j .Lexit
.L3: icmh %r0,4,0(%r5)
.L4: icmh %r0,2,0(%r5)
.L5: icmh %r0,1,0(%r5)
.L6: icm %r0,8,0(%r5)
.L7: icm %r0,4,0(%r5)
.L8: icm %r0,2,0(%r5)
.L9: icm %r0,1,0(%r5)
.L10: stg %r0,0(%r2,%r3)
la %r3,8(%r3)
aghi %r4,-1
j .L12
.L11: aghi %r1,-1
.L12: sllg %r4,%r4,3
algr %r4,%r1
algr %r2,%r3 # start of dst area to be zeroed
lgr %r3,%r4
slgr %r4,%r4
slgr %r5,%r5
.L13: mvcle %r2,%r4,0 # pad dst with zeroes
jo .L13
.Lexit: lg %r2,48(%r15) # return dst pointer
br %r14
END(strncpy)
libc_hidden_builtin_def (strncpy)
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