Add minf

Author: varkor

CHANGELOG.md

@@ -5,6 +5,10 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Added
+
+- minf
+
 ## [v0.1.2] - 2018-07-18
 
 ### Added

src/lib.rs

@@ -136,6 +136,8 @@ pub trait F32Ext: private::Sealed + Sized {
     fn acosh(self) -> Self;
 
     fn atanh(self) -> Self;
+
+    fn min(self, other: Self) -> Self;
 }
 
 impl F32Ext for f32 {
@@ -327,6 +329,11 @@ impl F32Ext for f32 {
     fn atanh(self) -> Self {
         atanhf(self)
     }
+
+    #[inline]
+    fn min(self, other: Self) -> Self {
+        minf(self, other)
+    }
 }
 
 /// Math support for `f64`

src/math/minf.rs

@@ -0,0 +1,13 @@
+#[inline]
+#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
+pub fn minf(x: f32, y: f32) -> f32 {
+    // IEEE754 says: minNum(x, y) is the canonicalized number x if x < y, y if y < x, the
+    // canonicalized number if one operand is a number and the other a quiet NaN. Otherwise it
+    // is either x or y, canonicalized (this means results might differ among implementations).
+    // When either x or y is a signalingNaN, then the result is according to 6.2.
+    //
+    // Since we do not support sNaN in Rust yet, we do not need to handle them.
+    // FIXME(nagisa): due to https://bugs.llvm.org/show_bug.cgi?id=33303 we canonicalize by
+    // multiplying by 1.0. Should switch to the `canonicalize` when it works.
+    (if y.is_nan() || x < y { x } else { y }) * 1.0
+}

src/math/mod.rs

@@ -166,6 +166,7 @@ mod tgamma;
 mod tgammaf;
 mod trunc;
 mod truncf;
+mod minf;
 
 // Use separated imports instead of {}-grouped imports for easier merging.
 pub use self::acos::acos;
@@ -272,6 +273,7 @@ pub use self::tgamma::tgamma;
 pub use self::tgammaf::tgammaf;
 pub use self::trunc::trunc;
 pub use self::truncf::truncf;
+pub use self::minf::minf;
 
 // Private modules
 mod expo2;