Add a generic version of fdim

Author: tgross35

libm/etc/function-definitions.json

@@ -289,13 +289,15 @@
     "fdim": {
         "sources": [
             "src/libm_helper.rs",
-            "src/math/fdim.rs"
+            "src/math/fdim.rs",
+            "src/math/generic/fdim.rs"
         ],
         "type": "f64"
     },
     "fdimf": {
         "sources": [
-            "src/math/fdimf.rs"
+            "src/math/fdimf.rs",
+            "src/math/generic/fdim.rs"
         ],
         "type": "f32"
     },

libm/src/math/fdim.rs

@@ -1,5 +1,3 @@
-use core::f64;
-
 /// Positive difference (f64)
 ///
 /// Determines the positive difference between arguments, returning:
@@ -10,13 +8,5 @@ use core::f64;
 /// A range error may occur.
 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
 pub fn fdim(x: f64, y: f64) -> f64 {
-    if x.is_nan() {
-        x
-    } else if y.is_nan() {
-        y
-    } else if x > y {
-        x - y
-    } else {
-        0.0
-    }
+    super::generic::fdim(x, y)
 }

libm/src/math/fdimf.rs

@@ -1,5 +1,3 @@
-use core::f32;
-
 /// Positive difference (f32)
 ///
 /// Determines the positive difference between arguments, returning:
@@ -10,13 +8,5 @@ use core::f32;
 /// A range error may occur.
 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
 pub fn fdimf(x: f32, y: f32) -> f32 {
-    if x.is_nan() {
-        x
-    } else if y.is_nan() {
-        y
-    } else if x > y {
-        x - y
-    } else {
-        0.0
-    }
+    super::generic::fdim(x, y)
 }

libm/src/math/generic/fdim.rs

@@ -0,0 +1,13 @@
+use super::super::Float;
+
+pub fn fdim<F: Float>(x: F, y: F) -> F {
+    if x.is_nan() {
+        x
+    } else if y.is_nan() {
+        y
+    } else if x > y {
+        x - y
+    } else {
+        F::ZERO
+    }
+}

libm/src/math/generic/mod.rs

@@ -1,7 +1,9 @@
 mod copysign;
 mod fabs;
+mod fdim;
 mod trunc;
 
 pub use copysign::copysign;
 pub use fabs::fabs;
+pub use fdim::fdim;
 pub use trunc::trunc;