Fix testing of the VEX.L (128/256-bit) flag in the x64 disassembler

Fix testing of the VEX.L (128/256-bit) flag in the x64 disassembler

The current code for testing the VEX.L flag, indicating whether
128-bit or 256-bit registers are being accessed, was erroneous
and always returned true (i.e. indicated 128-bit registers).

This patch fixes this behaviour and checks the flag correctly.

Ref: https://github.com/nodejs/node/issues/6151

BUG=

Committed: https://crrev.com/6336cc6b2babae5bd5ff2e654848656d63ab54ba
Cr-Commit-Position: refs/heads/master@{#35506}

[Anna Henningsen, 2016-04-12 16:12:41]

addaleax@gmail.com changed reviewers:
+ hablich@chromium.org

[Anna Henningsen, 2016-04-12 16:12:42]

The current code for testing the VEX.L flag, indicating whether 128-bit or
256-bit registers are being accessed, was erroneous and always returned true
(i.e. indicated 128-bit registers).

This patch fixes this behaviour and checks the flag correctly.

Ref: https://github.com/nodejs/node/issues/6151

This is likely not urgent.

[Yang, 2016-04-14 11:35:09]

yangguo@chromium.org changed reviewers:
+ yangguo@chromium.org

[Yang, 2016-04-14 11:35:10]

https://codereview.chromium.org/1875323002/diff/20001/src/x64/disasm-x64.cc
File src/x64/disasm-x64.cc (right):

https://codereview.chromium.org/1875323002/diff/20001/src/x64/disasm-x64.cc#n...
src/x64/disasm-x64.cc:362: return (checked & 4) == 0;
Same issue exists in disasm-ia32.cc. Could you fix that as well? Thanks.

[Anna Henningsen, 2016-04-14 19:46:03]

On 2016/04/14 11:35:10, Yang wrote:
> https://codereview.chromium.org/1875323002/diff/20001/src/x64/disasm-x64.cc
> File src/x64/disasm-x64.cc (right):
> 
>
https://codereview.chromium.org/1875323002/diff/20001/src/x64/disasm-x64.cc#n...
> src/x64/disasm-x64.cc:362: return (checked & 4) == 0;
> Same issue exists in disasm-ia32.cc. Could you fix that as well? Thanks.

Sure, just did.

[Yang, 2016-04-14 20:05:43]

On 2016/04/14 19:46:03, addaleax wrote:
> On 2016/04/14 11:35:10, Yang wrote:
> > https://codereview.chromium.org/1875323002/diff/20001/src/x64/disasm-x64.cc
> > File src/x64/disasm-x64.cc (right):
> > 
> >
>
https://codereview.chromium.org/1875323002/diff/20001/src/x64/disasm-x64.cc#n...
> > src/x64/disasm-x64.cc:362: return (checked & 4) == 0;
> > Same issue exists in disasm-ia32.cc. Could you fix that as well? Thanks.
> 
> Sure, just did.

lgtm.

[Yang, 2016-04-14 20:05:48]

The CQ bit was checked by yangguo@chromium.org

[commit-bot: I haz the power, 2016-04-14 20:05:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1875323002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1875323002/40001

[commit-bot: I haz the power, 2016-04-14 20:09:24]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-04-14 20:09:25]

Try jobs failed on following builders:
  v8_presubmit on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_presubmit/builds/13670)

[noordhuis, 2016-04-14 20:32:27]

On 2016/04/14 20:09:25, commit-bot: I haz the power wrote:
> Try jobs failed on following builders:
>   v8_presubmit on tryserver.v8 (JOB_FAILED,
> http://build.chromium.org/p/tryserver.v8/builders/v8_presubmit/builds/13670)

Anna, you need to sign the CLA
(https://code.google.com/legal/individual-cla-v1.0.html - you're a student,
right?) and add your name and email address to the AUTHORS file.  Keep it in
alphabetical order, the presubmit bot is picky about that.

Individual CLAs are processed automatically, IIRC; you should be able to
resubmit after that.

[Anna Henningsen, 2016-04-14 20:45:47]

On 2016/04/14 20:32:27, noordhuis wrote:
> Anna, you need to sign the CLA
> (https://code.google.com/legal/individual-cla-v1.0.html - you're a student,
> right?) and add your name and email address to the AUTHORS file.  Keep it in
> alphabetical order, the presubmit bot is picky about that.
> 
> Individual CLAs are processed automatically, IIRC; you should be able to
> resubmit after that.

The CLA should already have been signed, but yeah, sorry, updated again and
added my name to the AUTHORS list (I guess the commits here are begin squashed
anyway?).

[Yang, 2016-04-15 03:50:28]

The CQ bit was checked by yangguo@chromium.org

[Yang, 2016-04-15 03:50:28]

The patchset sent to the CQ was uploaded after l-g-t-m from yangguo@chromium.org
Link to the patchset: https://codereview.chromium.org/1875323002/#ps60001
(title: "Add me (addaleax@gmail.com) to the AUTHORS file")

[commit-bot: I haz the power, 2016-04-15 03:50:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1875323002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1875323002/60001

[commit-bot: I haz the power, 2016-04-15 06:23:36]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-04-15 06:24:40]

Description was changed from

==========
Fix testing of the VEX.L (128/256-bit) flag in the x64 disassembler

The current code for testing the VEX.L flag, indicating whether
128-bit or 256-bit registers are being accessed, was erroneous
and always returned true (i.e. indicated 128-bit registers).

This patch fixes this behaviour and checks the flag correctly.

Ref: https://github.com/nodejs/node/issues/6151

BUG=
==========

to

==========
Fix testing of the VEX.L (128/256-bit) flag in the x64 disassembler

The current code for testing the VEX.L flag, indicating whether
128-bit or 256-bit registers are being accessed, was erroneous
and always returned true (i.e. indicated 128-bit registers).

This patch fixes this behaviour and checks the flag correctly.

Ref: https://github.com/nodejs/node/issues/6151

BUG=

Committed: https://crrev.com/6336cc6b2babae5bd5ff2e654848656d63ab54ba
Cr-Commit-Position: refs/heads/master@{#35506}
==========

[commit-bot: I haz the power, 2016-04-15 06:24:41]

Patchset 4 (id:??) landed as
https://crrev.com/6336cc6b2babae5bd5ff2e654848656d63ab54ba
Cr-Commit-Position: refs/heads/master@{#35506}