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91 lines
2.6 KiB
ArmAsm
91 lines
2.6 KiB
ArmAsm
/* strncpy - copy at most n characters from a string from source to
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destination. 64 bit S/390 version
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Copyright (C) 2001-2014 Free Software Foundation, Inc.
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Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/* INPUT PARAMETERS
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%r2 = address of destination (dst)
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%r3 = address of source (src)
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%r4 = max of bytes to copy. */
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#include "sysdep.h"
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#include "asm-syntax.h"
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ENTRY(strncpy)
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.text
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stg %r2,48(%r15) # save dst pointer
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slgr %r2,%r3 # %r3 points to src, %r2+%r3 to dst
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lghi %r1,7
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ngr %r1,%r4 # last 3 bits of # bytes
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srlg %r4,%r4,3
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ltgr %r4,%r4 # less than 8 bytes to copy ?
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jz .L1
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bras %r5,.L0 # enter loop & load address of a 0
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.long 0
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.L0: icmh %r0,8,0(%r3) # first byte
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jz .L3
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icmh %r0,4,1(%r3) # second byte
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jz .L4
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icmh %r0,2,2(%r3) # third byte
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jz .L5
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icmh %r0,1,3(%r3) # fourth byte
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jz .L6
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icm %r0,8,4(%r3) # fifth byte
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jz .L7
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icm %r0,4,5(%r3) # sixth byte
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jz .L8
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icm %r0,2,6(%r3) # seventh byte
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jz .L9
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icm %r0,1,7(%r3) # eigth byte
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jz .L10
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stg %r0,0(%r2,%r3) # store all eight to dest.
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la %r3,8(%r3)
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brct %r4,.L0
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.L1: ltgr %r1,%r1
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jz .Lexit
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.L2: icm %r0,1,0(%r3)
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stc %r0,0(%r2,%r3)
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la %r3,1(%r3)
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jz .L11
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brct %r1,.L2
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j .Lexit
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.L3: icmh %r0,4,0(%r5)
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.L4: icmh %r0,2,0(%r5)
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.L5: icmh %r0,1,0(%r5)
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.L6: icm %r0,8,0(%r5)
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.L7: icm %r0,4,0(%r5)
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.L8: icm %r0,2,0(%r5)
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.L9: icm %r0,1,0(%r5)
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.L10: stg %r0,0(%r2,%r3)
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la %r3,8(%r3)
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aghi %r4,-1
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j .L12
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.L11: aghi %r1,-1
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.L12: sllg %r4,%r4,3
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algr %r4,%r1
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algr %r2,%r3 # start of dst area to be zeroed
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lgr %r3,%r4
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slgr %r4,%r4
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slgr %r5,%r5
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.L13: mvcle %r2,%r4,0 # pad dst with zeroes
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jo .L13
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.Lexit: lg %r2,48(%r15) # return dst pointer
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br %r14
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END(strncpy)
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libc_hidden_builtin_def (strncpy)
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