1 files changed, 91 insertions, 0 deletions
diff --git a/src/math/dim.go b/src/math/dim.go
new file mode 100644
index 0000000..6a857bb
--- /dev/null
+++ b/src/math/dim.go
@@ -0,0 +1,91 @@
+// 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 math
+
+// Dim returns the maximum of x-y or 0.
+//
+// Special cases are:
+//	Dim(+Inf, +Inf) = NaN
+//	Dim(-Inf, -Inf) = NaN
+//	Dim(x, NaN) = Dim(NaN, x) = NaN
+func Dim(x, y float64) float64 {
+	// The special cases result in NaN after the subtraction:
+	//      +Inf - +Inf = NaN
+	//      -Inf - -Inf = NaN
+	//       NaN - y    = NaN
+	//         x - NaN  = NaN
+	v := x - y
+	if v <= 0 {
+		// v is negative or 0
+		return 0
+	}
+	// v is positive or NaN
+	return v
+}
+
+// Max returns the larger of x or y.
+//
+// Special cases are:
+//	Max(x, +Inf) = Max(+Inf, x) = +Inf
+//	Max(x, NaN) = Max(NaN, x) = NaN
+//	Max(+0, ±0) = Max(±0, +0) = +0
+//	Max(-0, -0) = -0
+func Max(x, y float64) float64 {
+	if haveArchMax {
+		return archMax(x, y)
+	}
+	return max(x, y)
+}
+
+func max(x, y float64) float64 {
+	// special cases
+	switch {
+	case IsInf(x, 1) || IsInf(y, 1):
+		return Inf(1)
+	case IsNaN(x) || IsNaN(y):
+		return NaN()
+	case x == 0 && x == y:
+		if Signbit(x) {
+			return y
+		}
+		return x
+	}
+	if x > y {
+		return x
+	}
+	return y
+}
+
+// Min returns the smaller of x or y.
+//
+// Special cases are:
+//	Min(x, -Inf) = Min(-Inf, x) = -Inf
+//	Min(x, NaN) = Min(NaN, x) = NaN
+//	Min(-0, ±0) = Min(±0, -0) = -0
+func Min(x, y float64) float64 {
+	if haveArchMin {
+		return archMin(x, y)
+	}
+	return min(x, y)
+}
+
+func min(x, y float64) float64 {
+	// special cases
+	switch {
+	case IsInf(x, -1) || IsInf(y, -1):
+		return Inf(-1)
+	case IsNaN(x) || IsNaN(y):
+		return NaN()
+	case x == 0 && x == y:
+		if Signbit(x) {
+			return x
+		}
+		return y
+	}
+	if x < y {
+		return x
+	}
+	return y
+}