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Bug ID: JDK-8005522 use fast-string instructions on x86 for zeroing
JDK-8005522 : use fast-string instructions on x86 for zeroing

Details
Type:
Enhancement
Submit Date:
2012-12-26
Status:
Resolved
Updated Date:
2013-04-30
Project Name:
JDK
Resolved Date:
2013-01-04
Component:
hotspot
OS:
Sub-Component:
compiler
CPU:
x86
Priority:
P4
Resolution:
Fixed
Affected Versions:
Fixed Versions:
hs25 (b15)

Related Reports
Backport:
Backport:
Backport:
Relates:

Sub Tasks

Description
New x86 processors enhanced the operation of the REP MOVSB and REP STOSB instructions. A processors supports these enhancements if CPUID.(EAX=07H, ECX=0H):EBX[bit 9] is 1 (ERMS bit). VM uses stosq/stosd instructions to zero new java objects, replace them with fast-string stosb instructions when they are available. Note: we can't use REP MOVSB for arraycopy because it is not JMM compliant (not atomic and out of order).
                                    

Comments
URL:   http://hg.openjdk.java.net/hsx/hotspot-comp/hotspot/rev/00af3a3a8df4
User:  kvn
Date:  2013-01-04 01:05:05 +0000

                                     
2013-01-04
URL:   http://hg.openjdk.java.net/hsx/hsx25/hotspot/rev/00af3a3a8df4
User:  amurillo
Date:  2013-01-11 12:07:43 +0000

                                     
2013-01-11



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