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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
110 lines
3.0 KiB
ArmAsm
110 lines
3.0 KiB
ArmAsm
/* Copyright (C) 1996-2021 Free Software Foundation, Inc.
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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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<https://www.gnu.org/licenses/>. */
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/* Fill a block of memory with zeros. Optimized for the Alpha architecture:
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- memory accessed as aligned quadwords only
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- destination memory not read unless needed for good cache behaviour
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- basic blocks arranged to optimize branch prediction for full-quadword
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aligned memory blocks.
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- partial head and tail quadwords constructed with byte-mask instructions
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This is generally scheduled for the EV5 (got to look out for my own
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interests :-), but with EV4 needs in mind. There *should* be no more
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stalls for the EV4 than there are for the EV5.
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*/
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#include <sysdep.h>
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.set noat
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.set noreorder
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.text
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.type __bzero, @function
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.globl __bzero
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.usepv __bzero, USEPV_PROF
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cfi_startproc
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/* On entry to this basic block:
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t3 == loop counter
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t4 == bytes in partial final word
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a0 == possibly misaligned destination pointer */
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.align 3
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bzero_loop:
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beq t3, $tail #
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blbc t3, 0f # skip single store if count even
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stq_u zero, 0(a0) # e0 : store one word
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subq t3, 1, t3 # .. e1 :
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addq a0, 8, a0 # e0 :
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beq t3, $tail # .. e1 :
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0: stq_u zero, 0(a0) # e0 : store two words
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subq t3, 2, t3 # .. e1 :
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stq_u zero, 8(a0) # e0 :
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addq a0, 16, a0 # .. e1 :
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bne t3, 0b # e1 :
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$tail: bne t4, 1f # is there a tail to do?
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ret # no
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1: ldq_u t0, 0(a0) # yes, load original data
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mskqh t0, t4, t0 #
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stq_u t0, 0(a0) #
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ret #
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__bzero:
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#ifdef PROF
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ldgp gp, 0(pv)
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lda AT, _mcount
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jsr AT, (AT), _mcount
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#endif
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mov a0, v0 # e0 : move return value in place
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beq a1, $done # .. e1 : early exit for zero-length store
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and a0, 7, t1 # e0 :
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addq a1, t1, a1 # e1 : add dest misalignment to count
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srl a1, 3, t3 # e0 : loop = count >> 3
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and a1, 7, t4 # .. e1 : find number of bytes in tail
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unop # :
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beq t1, bzero_loop # e1 : aligned head, jump right in
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ldq_u t0, 0(a0) # e0 : load original data to mask into
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cmpult a1, 8, t2 # .. e1 : is this a sub-word set?
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bne t2, $oneq # e1 :
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mskql t0, a0, t0 # e0 : we span words. finish this partial
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subq t3, 1, t3 # e0 :
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addq a0, 8, a0 # .. e1 :
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stq_u t0, -8(a0) # e0 :
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br bzero_loop # .. e1 :
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.align 3
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$oneq:
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mskql t0, a0, t2 # e0 :
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mskqh t0, a1, t3 # e0 :
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or t2, t3, t0 # e1 :
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stq_u t0, 0(a0) # e0 :
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$done: ret
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cfi_endproc
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weak_alias (__bzero, bzero)
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