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authorRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
committerRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
commitc007ce824d9a4fccb148f9204e04c23ed2984b71 (patch)
tree7dcac257114ef5c446be5b7b68c27dea230b7c09 /src/runtime/complex.go
parent220a6de47eced55956eb8af8d643d4f5b67fd634 (diff)
downloadgo-c007ce824d9a4fccb148f9204e04c23ed2984b71.tar.gz
go-c007ce824d9a4fccb148f9204e04c23ed2984b71.zip
build: move package sources from src/pkg to src
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.
Diffstat (limited to 'src/runtime/complex.go')
-rw-r--r--src/runtime/complex.go52
1 files changed, 52 insertions, 0 deletions
diff --git a/src/runtime/complex.go b/src/runtime/complex.go
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+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime
+
+func complex128div(n complex128, d complex128) complex128 {
+ // Special cases as in C99.
+ ninf := real(n) == posinf || real(n) == neginf ||
+ imag(n) == posinf || imag(n) == neginf
+ dinf := real(d) == posinf || real(d) == neginf ||
+ imag(d) == posinf || imag(d) == neginf
+
+ nnan := !ninf && (real(n) != real(n) || imag(n) != imag(n))
+ dnan := !dinf && (real(d) != real(d) || imag(d) != imag(d))
+
+ switch {
+ case nnan || dnan:
+ return complex(nan, nan)
+ case ninf && !dinf:
+ return complex(posinf, posinf)
+ case !ninf && dinf:
+ return complex(0, 0)
+ case real(d) == 0 && imag(d) == 0:
+ if real(n) == 0 && imag(n) == 0 {
+ return complex(nan, nan)
+ } else {
+ return complex(posinf, posinf)
+ }
+ default:
+ // Standard complex arithmetic, factored to avoid unnecessary overflow.
+ a := real(d)
+ if a < 0 {
+ a = -a
+ }
+ b := imag(d)
+ if b < 0 {
+ b = -b
+ }
+ if a <= b {
+ ratio := real(d) / imag(d)
+ denom := real(d)*ratio + imag(d)
+ return complex((real(n)*ratio+imag(n))/denom,
+ (imag(n)*ratio-real(n))/denom)
+ } else {
+ ratio := imag(d) / real(d)
+ denom := imag(d)*ratio + real(d)
+ return complex((imag(n)*ratio+real(n))/denom,
+ (imag(n)-real(n)*ratio)/denom)
+ }
+ }
+}