From 758ff64c69e34965f8af5b2d6ffd65e8d7ab2150 Mon Sep 17 00:00:00 2001
From: Ondřej Surý <ondrej@sury.org>
Date: Mon, 14 Feb 2011 13:23:51 +0100
Subject: Imported Upstream version 2011-02-01.1

---
 src/pkg/math/frexp.go | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

(limited to 'src/pkg/math/frexp.go')

diff --git a/src/pkg/math/frexp.go b/src/pkg/math/frexp.go
index 203219c0d..867b78f36 100644
--- a/src/pkg/math/frexp.go
+++ b/src/pkg/math/frexp.go
@@ -8,6 +8,11 @@ package math
 // and an integral power of two.
 // It returns frac and exp satisfying f == frac × 2**exp,
 // with the absolute value of frac in the interval [½, 1).
+//
+// Special cases are:
+//	Frexp(±0) = ±0, 0
+//	Frexp(±Inf) = ±Inf, 0
+//	Frexp(NaN) = NaN, 0
 func Frexp(f float64) (frac float64, exp int) {
 	// TODO(rsc): Remove manual inlining of IsNaN, IsInf
 	// when compiler does it for us
@@ -18,8 +23,9 @@ func Frexp(f float64) (frac float64, exp int) {
 	case f < -MaxFloat64 || f > MaxFloat64 || f != f: // IsInf(f, 0) || IsNaN(f):
 		return f, 0
 	}
+	f, exp = normalize(f)
 	x := Float64bits(f)
-	exp = int((x>>shift)&mask) - bias + 1
+	exp += int((x>>shift)&mask) - bias + 1
 	x &^= mask << shift
 	x |= (-1 + bias) << shift
 	frac = Float64frombits(x)
-- 
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