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b24413180f
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
213 lines
7 KiB
ArmAsm
213 lines
7 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* arch/alpha/lib/ev6-clear_user.S
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* 21264 version contributed by Rick Gorton <rick.gorton@alpha-processor.com>
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*
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* Zero user space, handling exceptions as we go.
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*
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* We have to make sure that $0 is always up-to-date and contains the
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* right "bytes left to zero" value (and that it is updated only _after_
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* a successful copy). There is also some rather minor exception setup
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* stuff.
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*
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* Much of the information about 21264 scheduling/coding comes from:
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* Compiler Writer's Guide for the Alpha 21264
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* abbreviated as 'CWG' in other comments here
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* ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html
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* Scheduling notation:
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* E - either cluster
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* U - upper subcluster; U0 - subcluster U0; U1 - subcluster U1
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* L - lower subcluster; L0 - subcluster L0; L1 - subcluster L1
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* Try not to change the actual algorithm if possible for consistency.
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* Determining actual stalls (other than slotting) doesn't appear to be easy to do.
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* From perusing the source code context where this routine is called, it is
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* a fair assumption that significant fractions of entire pages are zeroed, so
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* it's going to be worth the effort to hand-unroll a big loop, and use wh64.
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* ASSUMPTION:
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* The believed purpose of only updating $0 after a store is that a signal
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* may come along during the execution of this chunk of code, and we don't
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* want to leave a hole (and we also want to avoid repeating lots of work)
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*/
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#include <asm/export.h>
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/* Allow an exception for an insn; exit if we get one. */
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#define EX(x,y...) \
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99: x,##y; \
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.section __ex_table,"a"; \
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.long 99b - .; \
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lda $31, $exception-99b($31); \
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.previous
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.set noat
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.set noreorder
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.align 4
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.globl __clear_user
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.ent __clear_user
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.frame $30, 0, $26
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.prologue 0
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# Pipeline info : Slotting & Comments
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__clear_user:
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and $17, $17, $0
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and $16, 7, $4 # .. E .. .. : find dest head misalignment
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beq $0, $zerolength # U .. .. .. : U L U L
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addq $0, $4, $1 # .. .. .. E : bias counter
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and $1, 7, $2 # .. .. E .. : number of misaligned bytes in tail
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# Note - we never actually use $2, so this is a moot computation
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# and we can rewrite this later...
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srl $1, 3, $1 # .. E .. .. : number of quadwords to clear
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beq $4, $headalign # U .. .. .. : U L U L
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/*
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* Head is not aligned. Write (8 - $4) bytes to head of destination
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* This means $16 is known to be misaligned
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*/
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EX( ldq_u $5, 0($16) ) # .. .. .. L : load dst word to mask back in
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beq $1, $onebyte # .. .. U .. : sub-word store?
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mskql $5, $16, $5 # .. U .. .. : take care of misaligned head
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addq $16, 8, $16 # E .. .. .. : L U U L
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EX( stq_u $5, -8($16) ) # .. .. .. L :
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subq $1, 1, $1 # .. .. E .. :
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addq $0, $4, $0 # .. E .. .. : bytes left -= 8 - misalignment
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subq $0, 8, $0 # E .. .. .. : U L U L
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.align 4
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/*
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* (The .align directive ought to be a moot point)
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* values upon initial entry to the loop
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* $1 is number of quadwords to clear (zero is a valid value)
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* $2 is number of trailing bytes (0..7) ($2 never used...)
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* $16 is known to be aligned 0mod8
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*/
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$headalign:
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subq $1, 16, $4 # .. .. .. E : If < 16, we can not use the huge loop
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and $16, 0x3f, $2 # .. .. E .. : Forward work for huge loop
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subq $2, 0x40, $3 # .. E .. .. : bias counter (huge loop)
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blt $4, $trailquad # U .. .. .. : U L U L
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/*
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* We know that we're going to do at least 16 quads, which means we are
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* going to be able to use the large block clear loop at least once.
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* Figure out how many quads we need to clear before we are 0mod64 aligned
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* so we can use the wh64 instruction.
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*/
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nop # .. .. .. E
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nop # .. .. E ..
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nop # .. E .. ..
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beq $3, $bigalign # U .. .. .. : U L U L : Aligned 0mod64
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$alignmod64:
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EX( stq_u $31, 0($16) ) # .. .. .. L
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addq $3, 8, $3 # .. .. E ..
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subq $0, 8, $0 # .. E .. ..
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nop # E .. .. .. : U L U L
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nop # .. .. .. E
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subq $1, 1, $1 # .. .. E ..
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addq $16, 8, $16 # .. E .. ..
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blt $3, $alignmod64 # U .. .. .. : U L U L
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$bigalign:
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/*
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* $0 is the number of bytes left
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* $1 is the number of quads left
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* $16 is aligned 0mod64
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* we know that we'll be taking a minimum of one trip through
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* CWG Section 3.7.6: do not expect a sustained store rate of > 1/cycle
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* We are _not_ going to update $0 after every single store. That
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* would be silly, because there will be cross-cluster dependencies
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* no matter how the code is scheduled. By doing it in slightly
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* staggered fashion, we can still do this loop in 5 fetches
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* The worse case will be doing two extra quads in some future execution,
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* in the event of an interrupted clear.
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* Assumes the wh64 needs to be for 2 trips through the loop in the future
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* The wh64 is issued on for the starting destination address for trip +2
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* through the loop, and if there are less than two trips left, the target
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* address will be for the current trip.
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*/
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nop # E :
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nop # E :
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nop # E :
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bis $16,$16,$3 # E : U L U L : Initial wh64 address is dest
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/* This might actually help for the current trip... */
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$do_wh64:
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wh64 ($3) # .. .. .. L1 : memory subsystem hint
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subq $1, 16, $4 # .. .. E .. : Forward calculation - repeat the loop?
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EX( stq_u $31, 0($16) ) # .. L .. ..
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subq $0, 8, $0 # E .. .. .. : U L U L
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addq $16, 128, $3 # E : Target address of wh64
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EX( stq_u $31, 8($16) ) # L :
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EX( stq_u $31, 16($16) ) # L :
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subq $0, 16, $0 # E : U L L U
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nop # E :
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EX( stq_u $31, 24($16) ) # L :
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EX( stq_u $31, 32($16) ) # L :
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subq $0, 168, $5 # E : U L L U : two trips through the loop left?
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/* 168 = 192 - 24, since we've already completed some stores */
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subq $0, 16, $0 # E :
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EX( stq_u $31, 40($16) ) # L :
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EX( stq_u $31, 48($16) ) # L :
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cmovlt $5, $16, $3 # E : U L L U : Latency 2, extra mapping cycle
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subq $1, 8, $1 # E :
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subq $0, 16, $0 # E :
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EX( stq_u $31, 56($16) ) # L :
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nop # E : U L U L
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nop # E :
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subq $0, 8, $0 # E :
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addq $16, 64, $16 # E :
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bge $4, $do_wh64 # U : U L U L
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$trailquad:
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# zero to 16 quadwords left to store, plus any trailing bytes
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# $1 is the number of quadwords left to go.
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#
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nop # .. .. .. E
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nop # .. .. E ..
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nop # .. E .. ..
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beq $1, $trailbytes # U .. .. .. : U L U L : Only 0..7 bytes to go
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$onequad:
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EX( stq_u $31, 0($16) ) # .. .. .. L
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subq $1, 1, $1 # .. .. E ..
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subq $0, 8, $0 # .. E .. ..
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nop # E .. .. .. : U L U L
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nop # .. .. .. E
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nop # .. .. E ..
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addq $16, 8, $16 # .. E .. ..
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bgt $1, $onequad # U .. .. .. : U L U L
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# We have an unknown number of bytes left to go.
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$trailbytes:
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nop # .. .. .. E
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nop # .. .. E ..
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nop # .. E .. ..
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beq $0, $zerolength # U .. .. .. : U L U L
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# $0 contains the number of bytes left to copy (0..31)
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# so we will use $0 as the loop counter
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# We know for a fact that $0 > 0 zero due to previous context
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$onebyte:
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EX( stb $31, 0($16) ) # .. .. .. L
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subq $0, 1, $0 # .. .. E .. :
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addq $16, 1, $16 # .. E .. .. :
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bgt $0, $onebyte # U .. .. .. : U L U L
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$zerolength:
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$exception: # Destination for exception recovery(?)
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nop # .. .. .. E :
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nop # .. .. E .. :
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nop # .. E .. .. :
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ret $31, ($26), 1 # L0 .. .. .. : L U L U
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.end __clear_user
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EXPORT_SYMBOL(__clear_user)
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