From 5caa9d15f26a088d3c75a183d70d4bf3a355200e Mon Sep 17 00:00:00 2001 From: Keith Randall Date: Thu, 15 Jan 2015 20:45:07 -0800 Subject: [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 (cherry picked from commit c6ddca2aec4218e1af7f51fad3b761afb33b4c20) Reviewed-on: https://go-review.googlesource.com/5001 --- src/math/big/int.go | 2 +- src/math/big/int_test.go | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/src/math/big/int.go b/src/math/big/int.go index d22e39e7c9..ade5c2fc8c 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 6070cf325d..2d762dbc89 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"}, -- cgit v1.2.3-54-g00ecf