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72 lines
2.3 KiB
ArmAsm
72 lines
2.3 KiB
ArmAsm
/* bcopy -- copy a block from source to destination. 64 bit S/390 version.
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This file is part of the GNU C Library.
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Copyright (C) 2000-2017 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 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 source
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%r3 = address of destination
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%r4 = number of bytes to copy. */
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#include "sysdep.h"
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#include "asm-syntax.h"
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.text
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ENTRY(__bcopy)
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ltgr %r1,%r4 # zero bcopy ?
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jz .L4
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clgr %r2,%r3 # check against destructive overlap
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jnl .L0
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algr %r1,%r2
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clgr %r1,%r3
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jh .L7
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.L0: aghi %r4,-1 # length - 1
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srlg %r1,%r4,8
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ltgr %r1,%r1 # < 256 bytes to move ?
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jz .L2
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cghi %r1,255 # > 1MB to move ?
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jh .L5
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.L1: mvc 0(256,%r3),0(%r2) # move in 256 byte chunks
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la %r2,256(%r2)
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la %r3,256(%r3)
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brctg %r1,.L1
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.L2: bras %r1,.L3 # setup base pointer for execute
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mvc 0(1,%r3),0(%r2) # instruction for execute
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.L3: ex %r4,0(%r1) # execute mvc with length ((%r4)&255)+1
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.L4: br %r14
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# data copies > 1MB are faster with mvcle.
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.L5: aghi %r4,1 # length + 1
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lgr %r5,%r4 # source length
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lgr %r4,%r2 # source address
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lgr %r2,%r3 # set destination
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lgr %r3,%r5 # destination length = source length
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.L6: mvcle %r2,%r4,0 # thats it, MVCLE is your friend
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jo .L6
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br %r14
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.L7: # destructive overlay, can not use mvcle
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lgr %r1,%r2 # bcopy is called with source,dest
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lgr %r2,%r3 # memmove with dest,source! Oh, well...
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lgr %r3,%r1
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jg HIDDEN_BUILTIN_JUMPTARGET(memmove)
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END(__bcopy)
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#ifndef NO_WEAK_ALIAS
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weak_alias (__bcopy, bcopy)
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#endif
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