cmov: signed integer support (#1280)

Adds impls of `Cmov`/`CmovEq` for `i8`, `i16`, `i32`, `i164`, and `i128`

Author: tarcieri

cmov/src/lib.rs

@@ -135,6 +135,44 @@ impl CmovEq for u128 {
     }
 }
 
+// Impl `Cmov*` by first casting to unsigned then using the unsigned `Cmov` impls
+// TODO(tarcieri): use `cast_unsigned`/`cast_signed` to get rid of the `=> u*`
+macro_rules! impl_cmov_traits_for_signed_ints {
+    ( $($int:ty => $uint:ty),+ ) => {
+        $(
+            impl Cmov for $int {
+                #[inline]
+                fn cmovnz(&mut self, value: &Self, condition: Condition) {
+                    let mut tmp = *self as $uint;
+                    tmp.cmovnz(&(*value as $uint), condition);
+                    *self = tmp as $int;
+                }
+
+                #[inline]
+                fn cmovz(&mut self, value: &Self, condition: Condition) {
+                    let mut tmp = *self as $uint;
+                    tmp.cmovz(&(*value as $uint), condition);
+                    *self = tmp as $int;
+                }
+            }
+
+            impl CmovEq for $int {
+                #[inline]
+                fn cmoveq(&self, rhs: &Self, input: Condition, output: &mut Condition) {
+                    (*self as $uint).cmoveq(&(*rhs as $uint), input, output);
+                }
+
+                #[inline]
+                fn cmovne(&self, rhs: &Self, input: Condition, output: &mut Condition) {
+                    (*self as $uint).cmovne(&(*rhs as $uint), input, output);
+                }
+            }
+        )+
+    };
+}
+
+impl_cmov_traits_for_signed_ints!(i8 => u8, i16 => u16, i32 => u32, i64 => u64, i128 => u128);
+
 impl<T: CmovEq> CmovEq for [T] {
     fn cmoveq(&self, rhs: &Self, input: Condition, output: &mut Condition) {
         let mut tmp = 1u8;

cmov/tests/lib.rs

@@ -1,3 +1,71 @@
+// TODO(tarcieri): test other `i*` types
+mod i64 {
+    use cmov::{Cmov, CmovEq};
+
+    pub const I64_A: i64 = 0x1111_1111_1111_1111;
+    pub const I64_B: i64 = -0x2222_2222_2222_2222;
+
+    #[test]
+    fn cmovz_works() {
+        let mut n = I64_A;
+
+        for cond in 1..0xFF {
+            n.cmovz(&I64_B, cond);
+            assert_eq!(n, I64_A);
+        }
+
+        n.cmovz(&I64_B, 0);
+        assert_eq!(n, I64_B);
+    }
+
+    #[test]
+    fn cmovnz_works() {
+        let mut n = I64_A;
+        n.cmovnz(&I64_B, 0);
+        assert_eq!(n, I64_A);
+
+        for cond in 1..0xFF {
+            let mut n = I64_A;
+            n.cmovnz(&I64_B, cond);
+            assert_eq!(n, I64_B);
+        }
+    }
+
+    #[test]
+    fn cmoveq_works() {
+        let mut o = 0u8;
+
+        for cond in 1..0xFFi64 {
+            cond.cmoveq(&cond, cond as u8, &mut o);
+            assert_eq!(o, cond as u8);
+            cond.cmoveq(&0, 0, &mut o);
+            assert_eq!(o, cond as u8);
+        }
+
+        I64_A.cmoveq(&I64_A, 43u8, &mut o);
+        assert_eq!(o, 43u8);
+        I64_A.cmoveq(&I64_B, 55u8, &mut o);
+        assert_eq!(o, 43u8);
+    }
+
+    #[test]
+    fn cmovne_works() {
+        let mut o = 0u8;
+
+        for cond in 1..0xFFi64 {
+            cond.cmovne(&0, cond as u8, &mut o);
+            assert_eq!(o, cond as u8);
+            cond.cmovne(&cond, 0, &mut o);
+            assert_eq!(o, cond as u8);
+        }
+
+        I64_A.cmovne(&I64_B, 55u8, &mut o);
+        assert_eq!(o, 55u8);
+        I64_A.cmovne(&I64_A, 12u8, &mut o);
+        assert_eq!(o, 55u8);
+    }
+}
+
 mod u8 {
     use cmov::{Cmov, CmovEq};