diff options
| author | Robert Griesemer <gri@golang.org> | 2015-02-13 20:15:40 -0800 |
|---|---|---|
| committer | Robert Griesemer <gri@golang.org> | 2015-02-14 04:22:56 +0000 |
| commit | b7bfb54eaa84a7de187df905ae8f74c8fed515f4 (patch) | |
| tree | b8639456ab66257e48d8b36bde280d3dc9039853 /src/math/big/float.go | |
| parent | a809dc7adb8065368c73900a8256048c55cde79b (diff) | |
| download | go-b7bfb54eaa84a7de187df905ae8f74c8fed515f4.tar.xz | |
math/big: fix aliasing bug in Float.Quo
TBR r, adonovan
Change-Id: I1a38e2d724bf1147c7307a7e5ae855c42c60428c
Reviewed-on: https://go-review.googlesource.com/4875
Reviewed-by: Robert Griesemer <gri@golang.org>
Diffstat (limited to 'src/math/big/float.go')
| -rw-r--r-- | src/math/big/float.go | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/src/math/big/float.go b/src/math/big/float.go index dd6700137b..314fd689ed 100644 --- a/src/math/big/float.go +++ b/src/math/big/float.go @@ -967,12 +967,16 @@ func (z *Float) uquo(x, y *Float) { // to shorten x for faster division. But we must be extra careful // with rounding in that case. + // Compute d before division since there may be aliasing of x.mant + // (via xadj) or y.mant with z.mant. + d := len(xadj) - len(y.mant) + // divide var r nat z.mant, r = z.mant.div(nil, xadj, y.mant) // determine exponent - e := int64(x.exp) - int64(y.exp) - int64(len(xadj)-len(y.mant)-len(z.mant))*_W + e := int64(x.exp) - int64(y.exp) - int64(d-len(z.mant))*_W // normalize mantissa z.setExp(e - int64(fnorm(z.mant))) |