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80 lines
2.4 KiB
ArmAsm
80 lines
2.4 KiB
ArmAsm
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/* strncpy - copy at most n characters from a string from source to
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destination. For IBM S390
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This file is part of the GNU C Library.
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Copyright (C) 2000 Free Software Foundation, Inc.
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Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
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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 Library General Public License as
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published by the Free Software Foundation ; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/*
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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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*/
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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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st %r2,24(%r15) # save dst pointer
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slr %r2,%r3 # %r3 points to src, %r2+%r3 to dst
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lhi %r1,3
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nr %r1,%r4 # last 2 bits of # bytes
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srl %r4,2
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ltr %r4,%r4 # less than 4 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: icm %r0,8,0(%r3) # first byte
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jz .L3
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icm %r0,4,1(%r3) # second byte
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jz .L4
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icm %r0,2,2(%r3) # third byte
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jz .L5
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icm %r0,1,3(%r3) # fourth byte
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jz .L6
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st %r0,0(%r2,%r3) # store all four to dest.
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la %r3,4(%r3)
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brct %r4,.L0
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.L1: ltr %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 .L7
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brct %r1,.L2
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j .Lexit
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.L3: icm %r0,4,0(%r5)
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.L4: icm %r0,2,0(%r5)
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.L5: icm %r0,1,0(%r5)
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.L6: st %r0,0(%r2,%r3)
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la %r3,4(%r3)
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ahi %r4,-1
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j .L8
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.L7: ahi %r1,-1
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.L8: sll %r4,2
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alr %r4,%r1
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alr %r2,%r3 # start of dst area to be zeroed
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lr %r3,%r4
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slr %r4,%r4
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slr %r5,%r5
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.L9: mvcle %r2,%r4,0 # pad dst with zeroes
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jo .L9
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.Lexit: l %r2,24(%r15) # return dst pointer
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br %r14
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END(strncpy)
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