Closed Bug 1103830 Opened 5 years ago Closed 5 years ago

x64 instruction decoder doesn't understand 0x40 REX prefix

Categories

(Core :: General, defect)

36 Branch
x86_64
Windows 7
defect
Not set

Tracking

()

RESOLVED FIXED
mozilla36

People

(Reporter: dmajor, Assigned: dmajor)

Details

Attachments

(1 file)

On the Windows 10 preview I found this:
00007ffd`28772e90 4053            push    rbx

WindowsDllDetourPatcher::CreateTrampoline fails because it doesn't understand the first byte.

0x40 is a REX prefix with none of the REX bits set. Before |push rbx| it is unnecessary, but we should accept it anyway.
Attached patch Support 0x40 REXSplinter Review
With my debugger's assembler I tested that all the instructions that we support for 0x41 also work with 0x40.
Assignee: nobody → dmajor
Attachment #8527453 - Flags: review?(m_kato)
Comment on attachment 8527453 [details] [diff] [review]
Support 0x40 REX

Review of attachment 8527453 [details] [diff] [review]:
-----------------------------------------------------------------

thanks!
Attachment #8527453 - Flags: review?(m_kato) → review+
https://hg.mozilla.org/mozilla-central/rev/b5023fc55b4c
Status: NEW → RESOLVED
Closed: 5 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla36
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