SVN=114204

1 files changed, 70 insertions, 0 deletions

diff --git a/src/lib/math/pow.go b/src/lib/math/pow.go
new file mode 100644
index 000000000..b2a954fb1
--- /dev/null
+++ b/src/lib/math/pow.go
@@ -0,0 +1,70 @@
+// Copyright 2009 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 pow
+
+import		sys "sys"
+import		floor "floor"
+import		sqrt "sqrt"
+import		log "log"
+import		exp "exp"
+export		pow
+
+/*
+	arg1 ^ arg2 (exponentiation)
+ */
+
+func
+pow(arg1,arg2 double) double
+{
+	var temp double;
+	var l long;
+
+	if arg2 < 0 {
+		return 1/pow(arg1, -arg2);
+	}
+	if arg1 <= 0 {
+		if(arg1 == 0) {
+			if arg2 <= 0 {
+				return sys.NaN();
+			}
+			return 0;
+		}
+
+		temp = floor.floor(arg2);
+		if temp != arg2 {
+			return sys.NaN();
+		}
+
+		l = long(temp);
+		if l&1 != 0 {
+			return -pow(-arg1, arg2);
+		}
+		return pow(-arg1, arg2);
+	}
+
+	temp = floor.floor(arg2);
+	if temp != arg2 {
+		if arg2-temp == .5 {
+			if temp == 0 {
+				return sqrt.sqrt(arg1);
+			}
+			return pow(arg1, temp) * sqrt.sqrt(arg1);
+		}
+		return exp.exp(arg2 * log.log(arg1));
+	}
+
+	l = long(temp);
+	temp = 1;
+	for {
+		if l&1 != 0 {
+			temp = temp*arg1;
+		}
+		l = l>>1;
+		if l == 0 {
+			return temp;
+		}
+		arg1 = arg1*arg1;
+	}
+}