Add saw2sin.sv

Handles inversion and reversing to create full sine wave from quarter wave

saw2sin.sv

@@ -0,0 +1,29 @@
+`default_nettype none
+
+module saw2sin
+( input  var [15:0] i_saw
+, output var [15:0] o_sin
+);
+
+logic invert;
+always_comb invert = i_saw[15];
+
+logic reverse;
+always_comb reverse = i_saw[14];
+
+logic [15:0] qsaw;
+always_comb qsaw = reverse
+  ? {~i_saw[13:0], 2'b01} // Reverse
+  : {i_saw[13:0], 2'b00}; // Normal
+
+logic [15:0] qsin;
+cordic cordic
+( .i_qph (qsaw)
+, .o_sin (qsin)
+);
+
+always_comb o_sin = invert
+  ? ~{1'b1, qsin[15:1]} + 1 // Invert
+  : {1'b1, qsin[15:1]};     // Normal
+
+endmodule