From: Shenghou Ma <minux.ma@gmail.com>
Date: Mon, 23 Apr 2012 15:47:36 +0000 (+0800)
Subject: math: ARM assembly implementation for Abs
X-Git-Tag: go1.1rc2~3342
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=e7e7b1c55ce7d73812caff018d02545f8f5740aa;p=gostls13.git

math: ARM assembly implementation for Abs

Obtained on 700MHz OMAP4460:
benchmark       old ns/op    new ns/op    delta
BenchmarkAbs           61           23  -61.63%

R=dave, remyoudompheng, mtj, rsc
CC=golang-dev
https://golang.org/cl/6094047
---

diff --git a/src/pkg/math/abs_arm.s b/src/pkg/math/abs_arm.s
index 23f6a2a2de..d7a406bec1 100644
--- a/src/pkg/math/abs_arm.s
+++ b/src/pkg/math/abs_arm.s
@@ -3,4 +3,9 @@
 // license that can be found in the LICENSE file.
 
 TEXT ·Abs(SB),7,$0
-	B ·abs(SB)
+	MOVW	lo+0(FP), R0
+	MOVW	hi+4(FP), R1
+	AND 	$((1<<31)-1), R1
+	MOVW	R0, resultlo+8(FP)
+	MOVW	R1, resulthi+12(FP)
+	RET