Bug 171118

Summary: X86-64 assembler doesn't handle xchg with byte register src
Product: WebKit Reporter: Michael Saboff <msaboff>
Component: JavaScriptCoreAssignee: Michael Saboff <msaboff>
Status: RESOLVED FIXED    
Severity: Normal CC: buildbot, fpizlo, keith_miller, mark.lam, saam, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Other   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch saam: review+

Description Michael Saboff 2017-04-21 10:29:50 PDT 
The Intel manual Vol 2A 3-3 shows that byte registers SPL and greater require a REX prefix byte.  The is done with the X86Assembler function oneByteOp8().  Use of that function was omitted when the xchg8_*() functions was added.
Comment 1 Radar WebKit Bug Importer 2017-04-21 10:32:14 PDT 
<rdar://problem/31760529>
Comment 2 Michael Saboff 2017-04-21 10:38:51 PDT 
Created attachment 307746 [details]
Patch

I did verify that all other byte ops use the *Op8() formatter function.
Comment 3 Michael Saboff 2017-04-21 10:42:33 PDT 
I fixed the spelling in the bug title, including the ChangeLog.
Comment 4 Michael Saboff 2017-04-21 11:28:53 PDT 
Committed r215618: <http://trac.webkit.org/changeset/215618>