alistair23-linux/arch/sh/lib64/udivdi3.S
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
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>
2017-11-02 11:10:55 +01:00

122 lines
3.2 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
.section .text..SHmedia32,"ax"
.align 2
.global __udivdi3
__udivdi3:
shlri r3,1,r4
nsb r4,r22
shlld r3,r22,r6
shlri r6,49,r5
movi 0xffffffffffffbaf1,r21 /* .l shift count 17. */
sub r21,r5,r1
mmulfx.w r1,r1,r4
mshflo.w r1,r63,r1
sub r63,r22,r20 // r63 == 64 % 64
mmulfx.w r5,r4,r4
pta large_divisor,tr0
addi r20,32,r9
msub.w r1,r4,r1
madd.w r1,r1,r1
mmulfx.w r1,r1,r4
shlri r6,32,r7
bgt/u r9,r63,tr0 // large_divisor
mmulfx.w r5,r4,r4
shlri r2,32+14,r19
addi r22,-31,r0
msub.w r1,r4,r1
mulu.l r1,r7,r4
addi r1,-3,r5
mulu.l r5,r19,r5
sub r63,r4,r4 // Negate to make sure r1 ends up <= 1/r2
shlri r4,2,r4 /* chop off leading %0000000000000000 001.00000000000 - or, as
the case may be, %0000000000000000 000.11111111111, still */
muls.l r1,r4,r4 /* leaving at least one sign bit. */
mulu.l r5,r3,r8
mshalds.l r1,r21,r1
shari r4,26,r4
shlld r8,r0,r8
add r1,r4,r1 // 31 bit unsigned reciprocal now in r1 (msb equiv. 0.5)
sub r2,r8,r2
/* Can do second step of 64 : 32 div now, using r1 and the rest in r2. */
shlri r2,22,r21
mulu.l r21,r1,r21
shlld r5,r0,r8
addi r20,30-22,r0
shlrd r21,r0,r21
mulu.l r21,r3,r5
add r8,r21,r8
mcmpgt.l r21,r63,r21 // See Note 1
addi r20,30,r0
mshfhi.l r63,r21,r21
sub r2,r5,r2
andc r2,r21,r2
/* small divisor: need a third divide step */
mulu.l r2,r1,r7
ptabs r18,tr0
addi r2,1,r2
shlrd r7,r0,r7
mulu.l r7,r3,r5
add r8,r7,r8
sub r2,r3,r2
cmpgt r2,r5,r5
add r8,r5,r2
/* could test r3 here to check for divide by zero. */
blink tr0,r63
large_divisor:
mmulfx.w r5,r4,r4
shlrd r2,r9,r25
shlri r25,32,r8
msub.w r1,r4,r1
mulu.l r1,r7,r4
addi r1,-3,r5
mulu.l r5,r8,r5
sub r63,r4,r4 // Negate to make sure r1 ends up <= 1/r2
shlri r4,2,r4 /* chop off leading %0000000000000000 001.00000000000 - or, as
the case may be, %0000000000000000 000.11111111111, still */
muls.l r1,r4,r4 /* leaving at least one sign bit. */
shlri r5,14-1,r8
mulu.l r8,r7,r5
mshalds.l r1,r21,r1
shari r4,26,r4
add r1,r4,r1 // 31 bit unsigned reciprocal now in r1 (msb equiv. 0.5)
sub r25,r5,r25
/* Can do second step of 64 : 32 div now, using r1 and the rest in r25. */
shlri r25,22,r21
mulu.l r21,r1,r21
pta no_lo_adj,tr0
addi r22,32,r0
shlri r21,40,r21
mulu.l r21,r7,r5
add r8,r21,r8
shlld r2,r0,r2
sub r25,r5,r25
bgtu/u r7,r25,tr0 // no_lo_adj
addi r8,1,r8
sub r25,r7,r25
no_lo_adj:
mextr4 r2,r25,r2
/* large_divisor: only needs a few adjustments. */
mulu.l r8,r6,r5
ptabs r18,tr0
/* bubble */
cmpgtu r5,r2,r5
sub r8,r5,r2
blink tr0,r63
/* Note 1: To shift the result of the second divide stage so that the result
always fits into 32 bits, yet we still reduce the rest sufficiently
would require a lot of instructions to do the shifts just right. Using
the full 64 bit shift result to multiply with the divisor would require
four extra instructions for the upper 32 bits (shift / mulu / shift / sub).
Fortunately, if the upper 32 bits of the shift result are nonzero, we
know that the rest after taking this partial result into account will
fit into 32 bits. So we just clear the upper 32 bits of the rest if the
upper 32 bits of the partial result are nonzero. */