Filled in missing methods on the fall-back non-SIMD code.

sub_crates/float4/src/lib.rs

@@ -680,8 +680,8 @@ mod x86_64_sse {
 
         /// Returns whether all four bools are false.
         ///
-        /// This is the `OR` operation on all the contained bools.  If even
-        /// one bool is true, this returns true.
+        /// This is the `NOT` operation on the result of `OR`ing all the
+        /// contained bools.  If even one bool is true, this returns false.
         #[inline(always)]
         pub fn is_all_false(&self) -> bool {
             let a = unsafe { *(&self.data as *const __m128 as *const u128) };
@@ -1269,21 +1269,25 @@ mod fallback {
         det
     }
 
-    /// Essentially a tuple of four bools, which will use SIMD operations
-    /// where possible on a platform.
-    #[cfg(feature = "simd_perf")]
-    #[derive(Debug, Copy, Clone)]
-    pub struct Bool4 {
-        data: bool32fx4,
-    }
-
-    #[cfg(not(feature = "simd_perf"))]
+    /// Essentially a tuple of four bools.
     #[derive(Debug, Copy, Clone)]
     pub struct Bool4 {
         data: [bool; 4],
     }
 
     impl Bool4 {
+        #[inline(always)]
+        pub fn new(a: bool, b: bool, c: bool, d: bool) -> Bool4 {
+            Bool4 { data: [a, b, c, d] }
+        }
+
+        #[inline(always)]
+        pub fn new_false() -> Bool4 {
+            Bool4 {
+                data: [false, false, false, false],
+            }
+        }
+
         /// Returns the value of the nth element.
         #[inline(always)]
         pub fn get_n(self, n: usize) -> bool {
@@ -1318,6 +1322,15 @@ mod fallback {
             self.get_n(3)
         }
 
+        /// Returns whether all four bools are false.
+        ///
+        /// This is the `NOT` operation on the result of `OR`ing all the
+        /// contained bools.  If even one bool is true, this returns false.
+        #[inline(always)]
+        pub fn is_all_false(&self) -> bool {
+            !(self.data[0] | self.data[1] | self.data[2] | self.data[3])
+        }
+
         #[inline]
         pub fn to_bitmask(self) -> u8 {
             (self.get_0() as u8)
@@ -1598,4 +1611,10 @@ mod tests {
 
         assert_eq!(r, 0b00001010);
     }
+
+    #[test]
+    fn bool4_is_all_false() {
+        assert_eq!(true, Bool4::new(false, false, false, false).is_all_false());
+        assert_eq!(false, Bool4::new(false, false, true, false).is_all_false());
+    }
 }