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The Go programming language
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Nigel Tao 0184081eb9 cmd/gc: recognize small TPTR64 values as small integer constants.
Given the following Go program:

func sum(s []int) int {
        ret := 0
        for _, x := range s {
                ret += x
        }
        return ret
}

6g would previously generate:

--- prog list "sum" ---
0000 (main.go:3) TEXT    sum+0(SB),$0-24
0001 (main.go:5) MOVQ    s+0(FP),CX
0002 (main.go:5) MOVL    s+8(FP),DI
0003 (main.go:5) MOVL    s+12(FP),BX
0004 (main.go:4) MOVL    $0,SI
0005 (main.go:5) MOVL    $0,AX
0006 (main.go:5) JMP     ,8
0007 (main.go:5) INCL    ,AX
0008 (main.go:5) CMPL    AX,DI
0009 (main.go:5) JGE     $0,16
0010 (main.go:5) MOVL    (CX),DX
0011 (main.go:5) MOVQ    $4,BX
0012 (main.go:5) ADDQ    CX,BX
0013 (main.go:5) MOVQ    BX,CX
0014 (main.go:6) ADDL    DX,SI
0015 (main.go:5) JMP     ,7
0016 (main.go:8) MOVL    SI,.noname+16(FP)
0017 (main.go:8) RET     ,

and now generates:

--- prog list "sum" ---
0000 (main.go:3) TEXT    sum+0(SB),$0-24
0001 (main.go:5) MOVQ    s+0(FP),CX
0002 (main.go:5) MOVL    s+8(FP),DI
0003 (main.go:5) MOVL    s+12(FP),BX
0004 (main.go:4) MOVL    $0,SI
0005 (main.go:5) MOVL    $0,AX
0006 (main.go:5) JMP     ,8
0007 (main.go:5) INCL    ,AX
0008 (main.go:5) CMPL    AX,DI
0009 (main.go:5) JGE     $0,14
0010 (main.go:5) MOVL    (CX),BP
0011 (main.go:5) ADDQ    $4,CX
0012 (main.go:6) ADDL    BP,SI
0013 (main.go:5) JMP     ,7
0014 (main.go:8) MOVL    SI,.noname+16(FP)
0015 (main.go:8) RET     ,

The key difference is that
0011 (main.go:5) MOVQ    $4,BX
0012 (main.go:5) ADDQ    CX,BX
0013 (main.go:5) MOVQ    BX,CX
has changed to
0011 (main.go:5) ADDQ    $4,CX

R=rsc, dave, remyoudompheng
CC=golang-dev
https://golang.org/cl/6506089
2012-09-11 19:45:28 +10:00
api api: add recent API additions to next.txt 2012-08-15 10:30:20 +10:00
doc doc css: topbar sticks to the top of large windows. 2012-09-11 11:38:47 +10:00
include src: Add support for 64-bit version of Plan 9 2012-08-31 13:21:13 -04:00
lib codereview.py: correct error handling without decorator 2012-09-01 19:55:29 -04:00
misc runtime: increase stack frame during cgo call on windows/amd64 2012-09-03 12:12:51 +10:00
src cmd/gc: recognize small TPTR64 values as small integer constants. 2012-09-11 19:45:28 +10:00
test gc: initial BOM is legal. 2012-09-10 13:03:07 -07:00
.hgignore build: update Makefile to track source code dependencies better 2012-03-13 03:31:11 +08:00
.hgtags tag go1.0.2 2012-06-14 13:18:10 +10:00
AUTHORS A+C: Oling Cat (individual CLA) 2012-09-05 14:52:12 +10:00
CONTRIBUTORS C: add Francesc Campoy (Google CLA) 2012-09-11 17:15:20 +10:00
favicon.ico
LICENSE doc: update licensing text one more time 2012-03-27 15:09:13 +11:00
PATENTS
README
robots.txt godoc: serve robots.txt raw 2011-02-19 05:46:20 +11:00
VERSION VERSION: check in a version file for the development branch 2012-08-24 13:01:50 -07:00

This is the source code repository for the Go programming language.  

For documentation about how to install and use Go,
visit http://golang.org/ or load doc/install.html in your web browser.

After installing Go, you can view a nicely formatted
doc/install.html by running godoc --http=:6060
and then visiting http://localhost:6060/doc/install.html.

Unless otherwise noted, the Go source files are distributed
under the BSD-style license found in the LICENSE file.

--

Binary Distribution Notes

If you have just untarred a binary Go distribution, you need to set
the environment variable $GOROOT to the full path of the go
directory (the one containing this README).  You can omit the
variable if you unpack it into /usr/local/go, or if you rebuild
from sources by running all.bash (see doc/install.html).
You should also add the Go binary directory $GOROOT/bin
to your shell's path.

For example, if you extracted the tar file into $HOME/go, you might
put the following in your .profile:

    export GOROOT=$HOME/go
    export PATH=$PATH:$GOROOT/bin

See doc/install.html for more details.