Revert "Conversion from a wider to a narrower IEEE-754 floating-point type"

This reverts commit baab4fd.

Author: alexcrichton

README.md

@@ -129,7 +129,7 @@ features = ["c"]
 - [x] arm/softfloat-alias.list
 - [x] arm/subdf3vfp.S
 - [x] arm/subsf3vfp.S
-- [x] arm/truncdfsf2vfp.S
+- [ ] arm/truncdfsf2vfp.S
 - [ ] arm/udivmodsi4.S (generic version is done)
 - [ ] arm/udivsi3.S (generic version is done)
 - [ ] arm/umodsi3.S (generic version is done)
@@ -186,7 +186,7 @@ features = ["c"]
 - [x] subdf3.c
 - [x] subsf3.c
 - [ ] truncdfhf2.c
-- [x] truncdfsf2.c
+- [ ] truncdfsf2.c
 - [ ] truncsfhf2.c
 - [x] udivdi3.c
 - [x] udivmoddi4.c

build.rs

@@ -174,6 +174,7 @@ mod c {
                 "subvdi3.c",
                 "subvsi3.c",
                 "truncdfhf2.c",
+                "truncdfsf2.c",
                 "truncsfhf2.c",
                 "ucmpdi2.c",
             ],

src/float/mod.rs

@@ -11,7 +11,6 @@ pub mod sub;
 pub mod mul;
 pub mod div;
 pub mod extend;
-pub mod truncate;
 
 /// Trait for some basic operations on floats
 pub trait Float:

src/float/truncate.rs

@@ -348,24 +348,6 @@ fn main() {
         "builtins::float::extend::__extendsfdf2vfp(a)");
     }
 
-    // float/truncate.rs
-    gen(|a: MyF64| {
-            if a.0.is_nan() {
-                return None;
-            }
-            Some(a.0 as f32)
-        },
-        "builtins::float::truncate::__truncdfsf2(a)");
-    if target_arch_arm {
-        gen(|a: LargeF64| {
-            if a.0.is_nan() {
-                return None;
-            }
-            Some(a.0 as f32)
-        },
-        "builtins::float::truncate::__truncdfsf2vfp(a)");
-    }
-
     // float/conv.rs
     gen(|a: MyF64| i64(a.0).ok(),
         "builtins::float::conv::__fixdfdi(a)");