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| author | Keith Randall <khr@golang.org> | 2015-01-15 20:45:07 -0800 |
|---|---|---|
| committer | Andrew Gerrand <adg@golang.org> | 2015-02-17 06:48:38 +0000 |
| commit | 5caa9d15f26a088d3c75a183d70d4bf3a355200e (patch) | |
| tree | 49a48e94ddb580a79fe6d4464babb3f841efe570 | |
| parent | b64f8f8764e975b98e2c5e0d77a424601ed75c29 (diff) | |
| download | go-5caa9d15f26a088d3c75a183d70d4bf3a355200e.tar.gz go-5caa9d15f26a088d3c75a183d70d4bf3a355200e.zip | |
[release-branch.go1.4] math/big: bug in AndNot(x,y) for x>0,y<0.
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 c6ddca2aec4218e1af7f51fad3b761afb33b4c20)
Reviewed-on: https://go-review.googlesource.com/5001
| -rw-r--r-- | src/math/big/int.go | 2 | ||||
| -rw-r--r-- | src/math/big/int_test.go | 1 |
2 files changed, 2 insertions, 1 deletions
diff --git a/src/math/big/int.go b/src/math/big/int.go index d22e39e7c94..ade5c2fc8cd 100644 --- a/src/math/big/int.go +++ b/src/math/big/int.go @@ -887,7 +887,7 @@ func (z *Int) AndNot(x, y *Int) *Int { } // x &^ (-y) == x &^ ^(y-1) == x & (y-1) - y1 := nat(nil).add(y.abs, natOne) + y1 := nat(nil).sub(y.abs, natOne) z.abs = z.abs.and(x.abs, y1) z.neg = false return z diff --git a/src/math/big/int_test.go b/src/math/big/int_test.go index 6070cf325d2..2d762dbc89f 100644 --- a/src/math/big/int_test.go +++ b/src/math/big/int_test.go @@ -1201,6 +1201,7 @@ var bitwiseTests = []struct { {"-0x01", "-0x01", "-0x01", "-0x01", "0x00", "0x00"}, {"0x07", "0x08", "0x00", "0x0f", "0x0f", "0x07"}, {"0x05", "0x0f", "0x05", "0x0f", "0x0a", "0x00"}, + {"0xff", "-0x0a", "0xf6", "-0x01", "-0xf7", "0x09"}, {"0x013ff6", "0x9a4e", "0x1a46", "0x01bffe", "0x01a5b8", "0x0125b0"}, {"-0x013ff6", "0x9a4e", "0x800a", "-0x0125b2", "-0x01a5bc", "-0x01c000"}, {"-0x013ff6", "-0x9a4e", "-0x01bffe", "-0x1a46", "0x01a5b8", "0x8008"}, |