Add initial prototype.

1-base/math/source/generic/pure/geometry/trigonometry/cached_rotation.ads

@@ -0,0 +1,30 @@
+with
+     ada.Numerics.generic_elementary_Functions;
+
+
+generic
+   type Float_type      is digits <>;
+   type Matrix_2x2_type is private;
+
+   with package  float_elementary_Functions is new ada.Numerics.generic_elementary_Functions (Float_type);
+   with function to_Matrix_2x2 (m11, m12,
+                                m21, m22 : Float_type) return Matrix_2x2_type;
+
+   slot_Count : Standard.Positive;
+
+package cached_Rotation
+--
+-- Caches 2x2 rotation matrices of angles for speed at the cost of precision.
+--
+is
+   pragma Optimize (Time);
+
+   function to_Rotation (Angle : in Float_type) return access constant Matrix_2x2_type;
+
+
+
+private
+
+   pragma Inline_Always (to_Rotation);
+
+end cached_Rotation;