add rotate_left/right

coresimd/ppsv/api/mod.rs

@@ -124,6 +124,8 @@ mod masks_select;
 mod scalar_shifts;
 #[macro_use]
 mod shifts;
+#[macro_use]
+mod rotates;
 
 /// Sealed trait used for constraining select implementations.
 pub trait Lanes<A> {}
@@ -191,6 +193,7 @@ macro_rules! simd_i_ty {
             [impl_bitwise_reductions, $id, $elem_ty],
             [impl_all_scalar_shifts, $id, $elem_ty],
             [impl_vector_shifts, $id, $elem_ty],
+            [impl_vector_rotates, $id, $elem_ty],
             [impl_hex_fmt, $id, $elem_ty],
             [impl_eq, $id],
             [impl_partial_eq, $id],
@@ -215,6 +218,7 @@ macro_rules! simd_i_ty {
                 test_bitwise_reductions!($id, !(0 as $elem_ty));
                 test_all_scalar_shift_ops!($id, $elem_ty);
                 test_vector_shift_ops!($id, $elem_ty);
+                test_vector_rotate_ops!($id, $elem_ty);
                 test_hex_fmt!($id, $elem_ty);
                 test_partial_eq!($id, 1 as $elem_ty, 0 as $elem_ty);
                 test_default!($id, $elem_ty);
@@ -245,6 +249,7 @@ macro_rules! simd_u_ty {
             [impl_bitwise_reductions, $id, $elem_ty],
             [impl_all_scalar_shifts, $id, $elem_ty],
             [impl_vector_shifts, $id, $elem_ty],
+            [impl_vector_rotates, $id, $elem_ty],
             [impl_hex_fmt, $id, $elem_ty],
             [impl_eq, $id],
             [impl_partial_eq, $id],
@@ -268,6 +273,7 @@ macro_rules! simd_u_ty {
                 test_bitwise_reductions!($id, !(0 as $elem_ty));
                 test_all_scalar_shift_ops!($id, $elem_ty);
                 test_vector_shift_ops!($id, $elem_ty);
+                test_vector_rotate_ops!($id, $elem_ty);
                 test_hex_fmt!($id, $elem_ty);
                 test_partial_eq!($id, 1 as $elem_ty, 0 as $elem_ty);
                 test_default!($id, $elem_ty);

coresimd/ppsv/api/rotates.rs

@@ -0,0 +1,83 @@
+//! Implements integer rotates.
+#![allow(unused)]
+
+macro_rules! impl_vector_rotates {
+    ($id:ident, $elem_ty:ident) => {
+        impl $id {
+            /// Shifts the bits of each lane to the left by the specified amount in
+            /// the corresponding lane of `n`, wrapping the truncated bits to
+            /// the end of the resulting integer.
+            ///
+            /// Please note this isn't the same operation as `<<`!. Also note it
+            /// isn't equivalent to `slice::rotate_left` (that can be implemented
+            /// with vector shuffles).
+            #[inline]
+            pub fn rotate_left(self, n: $id) -> $id {
+                const LANE_WIDTH: $elem_ty = ::mem::size_of::<$elem_ty>() as $elem_ty * 8;
+                // Protect against undefined behavior for over-long bit shifts
+                let n = n % LANE_WIDTH;
+                (self << n) | (self >> ((LANE_WIDTH - n) % LANE_WIDTH))
+            }
+
+            /// Shifts the bits of each lane to the right by the specified amount in
+            /// the corresponding lane of `n`, wrapping the truncated bits to
+            /// the beginning of the resulting integer.
+            ///
+            /// Please note this isn't the same operation as `>>`!. Also note it
+            /// isn't similar to `slice::rotate_right`, it doesn't move the vector's
+            /// lanes around. (that can be implemented with vector shuffles).
+            #[inline]
+            pub fn rotate_right(self, n: $id) -> $id {
+                const LANE_WIDTH: $elem_ty = ::mem::size_of::<$elem_ty>() as $elem_ty * 8;
+                // Protect against undefined behavior for over-long bit shifts
+                let n = n % LANE_WIDTH;
+                (self >> n) | (self << ((LANE_WIDTH - n) % LANE_WIDTH))
+            }
+        }
+    };
+}
+
+#[cfg(test)]
+macro_rules! test_vector_rotate_ops {
+    ($id:ident, $elem_ty:ident) => {
+        #[test]
+        fn rotate_ops() {
+            use coresimd::simd::$id;
+            use std::mem;
+            let z = $id::splat(0 as $elem_ty);
+            let o = $id::splat(1 as $elem_ty);
+            let t = $id::splat(2 as $elem_ty);
+            let f = $id::splat(4 as $elem_ty);
+
+            let max =
+                $id::splat((mem::size_of::<$elem_ty>() * 8 - 1) as $elem_ty);
+
+            // rotate_right
+            assert_eq!(z.rotate_right(z), z);
+            assert_eq!(z.rotate_right(o), z);
+            assert_eq!(z.rotate_right(t), z);
+
+            assert_eq!(o.rotate_right(z), o);
+            assert_eq!(t.rotate_right(z), t);
+            assert_eq!(f.rotate_right(z), f);
+            assert_eq!(f.rotate_right(max), f << 1);
+
+            assert_eq!(o.rotate_right(o), o << max);
+            assert_eq!(t.rotate_right(o), o);
+            assert_eq!(t.rotate_right(t), o << max);
+            assert_eq!(f.rotate_right(o), t);
+            assert_eq!(f.rotate_right(t), o);
+
+            // rotate_left
+            assert_eq!(z.rotate_left(z), z);
+            assert_eq!(o.rotate_left(z), o);
+            assert_eq!(t.rotate_left(z), t);
+            assert_eq!(f.rotate_left(z), f);
+            assert_eq!(f.rotate_left(max), t);
+
+            assert_eq!(o.rotate_left(o), t);
+            assert_eq!(o.rotate_left(t), f);
+            assert_eq!(t.rotate_left(o), f);
+        }
+    };
+}

coresimd/ppsv/api/shifts.rs

@@ -53,7 +53,6 @@ macro_rules! test_vector_shift_ops {
             assert_eq!(z >> z, z);
             assert_eq!(z >> o, z);
             assert_eq!(z >> t, z);
-            assert_eq!(z >> t, z);
 
             assert_eq!(o >> z, o);
             assert_eq!(t >> z, t);
@@ -65,7 +64,6 @@ macro_rules! test_vector_shift_ops {
             assert_eq!(t >> t, z);
             assert_eq!(f >> o, t);
             assert_eq!(f >> t, o);
-            assert_eq!(f >> max, z);
 
             // shl
             assert_eq!(z << z, z);