Initial commit!

src/unsigned/sub.rs

@@ -0,0 +1,76 @@
+use unsigned::add::unsafe_addition;
+
+pub fn subtract(res: &mut [u64], spare: &mut [u64], other: &[u64])
+{
+    for i in 0..res.len() {
+        res[i] = !res[i];
+    }
+    spare[0] = 1;
+    unsafe_addition(res, &spare);
+    unsafe_addition(res, &other);
+}
+
+macro_rules! subtraction_impls
+{
+    ($name: ident, $size: expr) => {
+        impl SubAssign for $name {
+            fn sub_assign(&mut self, rhs: $name) {
+                let mut temp = [0; $size];
+                subtract(&mut self.value, &mut temp, &rhs.value);
+            }
+        }
+
+        impl<'a> SubAssign<&'a $name> for $name {
+            fn sub_assign(&mut self, rhs: &$name) {
+                let mut temp = [0; $size];
+                subtract(&mut self.value, &mut temp, &rhs.value);
+            }
+        }
+
+        impl Sub for $name {
+            type Output = $name;
+
+            fn sub(self, rhs: $name) -> $name {
+                let mut res  = $name::zero();
+                let mut temp = [0; $size];
+                subtract(&mut res.value, &mut temp, &rhs.value);
+                res
+            }
+        }
+
+        impl<'a> Sub<$name> for &'a $name {
+            type Output = $name;
+
+            fn sub(self, rhs: $name) -> $name {
+                let mut res  = $name::zero();
+                let mut temp = [0; $size];
+                subtract(&mut res.value, &mut temp, &rhs.value);
+                res
+            }
+        }
+
+        impl<'a> Sub<&'a $name> for $name {
+            type Output = $name;
+
+            fn sub(self, rhs: &$name) -> $name {
+                let mut res  = $name::zero();
+                let mut temp = [0; $size];
+                subtract(&mut res.value, &mut temp, &rhs.value);
+                res
+            }
+        }
+
+        impl<'a,'b> Sub<&'a $name> for &'b $name {
+            type Output = $name;
+
+            fn sub(self, rhs: &$name) -> $name {
+                let mut res  = $name::zero();
+                let mut temp = [0; $size];
+                subtract(&mut res.value, &mut temp, &rhs.value);
+                res
+            }
+        }
+    }
+}
+
+//subtraction_impls!(U192,   3);