Issue 115580044: code review 115580044: liblink: shorter encoding for zeroing register

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Issue 115580044: code review 115580044: liblink: shorter encoding for zeroing register (Closed)

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Created:
10 years, 9 months ago by ruiu

Modified:
10 years, 9 months ago

Reviewers:
rsc

CC:
golang-codereviews, gobot, rsc

Visibility:
Public.

Description

liblink: shorter encoding for zeroing register Encode MOV $0, %ax as XOR %eax, %eax instead of XOR %rax, %rax. If an operand register does not need REX.w bit (i.e. not one of R8-R15), it is encoded in 2 bytes instead of 3 bytes.

Patch Set 1 #

Patch Set 2 : code review 115580044: liblink: shorter encoding for zeroing register #

Patch Set 3 : diff -r c6b7f7454ffc https://code.google.com/p/go #

Patch Set 4 : diff -r c6b7f7454ffc https://code.google.com/p/go #

Patch Set 5 : diff -r 0015a2541545 https://code.google.com/p/go #

Created: 10 years, 9 months ago

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		Unified diffs	Side-by-side diffs	Delta from patch set	Stats (+1 line, -0 lines)			Patch
	M	src/liblink/asm6.c	View		1 chunk	+1 line, -0 lines	0 comments	Download

Messages

Total messages: 4

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ruiu

Hello golang-codereviews@googlegroups.com, I'd like you to review this change to https://code.google.com/p/go

10 years, 9 months ago (2014-08-03 19:25:46 UTC) #1

ruiu

10 years, 9 months ago (2014-08-06 04:10:11 UTC) #4

*** Submitted as https://code.google.com/p/go/source/detail?r=4dff6ec65b25 ***

liblink: shorter encoding for zeroing register

Encode MOV $0, %ax as XOR %eax, %eax instead of
XOR %rax, %rax. If an operand register does not
need REX.w bit (i.e. not one of R8-R15), it is
encoded in 2 bytes instead of 3 bytes.

LGTM=rsc
R=golang-codereviews, gobot, rsc
CC=golang-codereviews
https://codereview.appspot.com/115580044

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