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math/big: AndNot(x,y) doesn't work when x is positive and y is negative #9609

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randall77 opened this issue Jan 16, 2015 · 1 comment
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math/big: AndNot(x,y) doesn't work when x is positive and y is negative #9609

randall77 opened this issue Jan 16, 2015 · 1 comment
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Go1.4.2

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@randall77
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package main

import (
"fmt"
"math/big"
)

func main() {
fmt.Println(new(big.Int).AndNot(big.NewInt(0xff), big.NewInt(-1)))
}

This should print 0. It does print 2.
The bug is in math/big/int.go:893, it should use sub, not add, as the comment in the previous line specifies.
@randall77 randall77 self-assigned this Jan 16, 2015
@randall77 randall77 added this to the Go1.4.2 milestone Jan 16, 2015
@mikioh mikioh changed the title math/big.AndNot(x,y) doesn't work when x is positive and y is negative math/big: AndNot(x,y) doesn't work when x is positive and y is negative Jan 16, 2015
gopherbot pushed a commit that referenced this issue Jan 17, 2015
@randall77
test: generate tests for arithmetic on narrow types
c3b459d 
Fixes #9607
Related to #9604
Inadvertently found #9609

Change-Id: I8a8ddf84ac72d3e18986fd8e9288734459f3f174
Reviewed-on: https://go-review.googlesource.com/2962
Reviewed-by: Minux Ma <minux@golang.org>
adg pushed a commit that referenced this issue Feb 17, 2015
@randall77 @adg
[release-branch.go1.4] math/big: bug in AndNot(x,y) for x>0,y<0.
5caa9d1 
The comment says to use (y-1), but then we did add(y.abs, natOne).  We meant sub.

Fixes #9609

Change-Id: I4fe4783326ca082c05588310a0af7895a48fc779
Reviewed-on: https://go-review.googlesource.com/2961
Reviewed-by: Robert Griesemer <gri@golang.org>
(cherry picked from commit c6ddca2)
Reviewed-on: https://go-review.googlesource.com/5001
@rsc
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rsc commented Feb 18, 2015

Not obvious why this was 1.4.2 worthy.

@golang golang locked and limited conversation to collaborators Jun 25, 2016
wheatman pushed a commit to wheatman/go-akaros that referenced this issue Jun 25, 2018
@randall77 @wheatman
[release-branch.go1.4] math/big: bug in AndNot(x,y) for x>0,y<0.
21685f6 
The comment says to use (y-1), but then we did add(y.abs, natOne).  We meant sub.

Fixes golang#9609

Change-Id: I4fe4783326ca082c05588310a0af7895a48fc779
Reviewed-on: https://go-review.googlesource.com/2961
Reviewed-by: Robert Griesemer <gri@golang.org>
(cherry picked from commit c6ddca2)
Reviewed-on: https://go-review.googlesource.com/5001
wheatman pushed a commit to wheatman/go-akaros that referenced this issue Jun 26, 2018
@randall77 @wheatman
[release-branch.go1.4] math/big: bug in AndNot(x,y) for x>0,y<0.
9c2c15d 
The comment says to use (y-1), but then we did add(y.abs, natOne).  We meant sub.

Fixes golang#9609

Change-Id: I4fe4783326ca082c05588310a0af7895a48fc779
Reviewed-on: https://go-review.googlesource.com/2961
Reviewed-by: Robert Griesemer <gri@golang.org>
(cherry picked from commit c6ddca2)
Reviewed-on: https://go-review.googlesource.com/5001
wheatman pushed a commit to wheatman/go-akaros that referenced this issue Jul 9, 2018
@randall77 @wheatman
[release-branch.go1.4] math/big: bug in AndNot(x,y) for x>0,y<0.
202d2e8 
The comment says to use (y-1), but then we did add(y.abs, natOne).  We meant sub.

Fixes golang#9609

Change-Id: I4fe4783326ca082c05588310a0af7895a48fc779
Reviewed-on: https://go-review.googlesource.com/2961
Reviewed-by: Robert Griesemer <gri@golang.org>
(cherry picked from commit c6ddca2)
Reviewed-on: https://go-review.googlesource.com/5001
wheatman pushed a commit to wheatman/go-akaros that referenced this issue Jul 20, 2018
@randall77 @wheatman
[release-branch.go1.4] math/big: bug in AndNot(x,y) for x>0,y<0.
467f56a 
The comment says to use (y-1), but then we did add(y.abs, natOne).  We meant sub.

Fixes golang#9609

Change-Id: I4fe4783326ca082c05588310a0af7895a48fc779
Reviewed-on: https://go-review.googlesource.com/2961
Reviewed-by: Robert Griesemer <gri@golang.org>
(cherry picked from commit c6ddca2)
Reviewed-on: https://go-review.googlesource.com/5001
wheatman pushed a commit to wheatman/go-akaros that referenced this issue Jul 30, 2018
@randall77 @wheatman
[release-branch.go1.4] math/big: bug in AndNot(x,y) for x>0,y<0.
d3b4acc 
The comment says to use (y-1), but then we did add(y.abs, natOne).  We meant sub.

Fixes golang#9609

Change-Id: I4fe4783326ca082c05588310a0af7895a48fc779
Reviewed-on: https://go-review.googlesource.com/2961
Reviewed-by: Robert Griesemer <gri@golang.org>
(cherry picked from commit c6ddca2)
Reviewed-on: https://go-review.googlesource.com/5001
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