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| author | Nigel Tao <nigeltao@golang.org> | 2020-10-22 23:59:00 +1100 |
|---|---|---|
| committer | Nigel Tao <nigeltao@golang.org> | 2020-10-22 21:12:43 +0000 |
| commit | 4ce9ea52c9ac48f85fba1233b6e7d563f89dff8b (patch) | |
| tree | 79fbfd45859e78c9b8d4f9a74f98d456b2cd8642 /src/strconv | |
| parent | c92bfac01e9e8319822f472fd11a51bf28762125 (diff) | |
| download | go-4ce9ea52c9ac48f85fba1233b6e7d563f89dff8b.tar.gz go-4ce9ea52c9ac48f85fba1233b6e7d563f89dff8b.zip | |
strconv: fix Eisel-Lemire for negative zero
This is somewhat academic (and no tests failed before this commit),
since func atof64 only calls func eiselLemire when func atof64exact
fails, and func atof64exact doesn't fail when parsing positive or
negative zeroes. But it's still worth fixing.
Change-Id: Ibe6ef4c8fd96827673b711d5456003fbc447e39c
Reviewed-on: https://go-review.googlesource.com/c/go/+/264140
Trust: Nigel Tao <nigeltao@golang.org>
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Diffstat (limited to 'src/strconv')
| -rw-r--r-- | src/strconv/eisel_lemire.go | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/strconv/eisel_lemire.go b/src/strconv/eisel_lemire.go index 00fadbdb96..5cd22a7e37 100644 --- a/src/strconv/eisel_lemire.go +++ b/src/strconv/eisel_lemire.go @@ -22,14 +22,17 @@ import ( "math/bits" ) -func eiselLemire(man uint64, exp10 int, neg bool) (ret float64, ok bool) { +func eiselLemire(man uint64, exp10 int, neg bool) (f float64, ok bool) { // The terse comments in this function body refer to sections of the // https://nigeltao.github.io/blog/2020/eisel-lemire.html blog post. // Exp10 Range. const exp10Min, exp10Max = -307, +288 if man == 0 { - return 0, true + if neg { + f = math.Float64frombits(0x80000000_00000000) // Negative zero. + } + return f, true } if exp10 < exp10Min || exp10Max < exp10 { return 0, false |