b2xx: Updating FPGA source with recent bugfixes.

Original-commit: 4b4365a517938b365af57674a3ab1462432c2c3a

lib/control/binary_encoder.v

@@ -0,0 +1,42 @@
+
+`define LOG2(N) (\
+                 N < 2 ? 0 : \
+                 N < 4 ? 1 : \
+                 N < 8 ? 2 : \
+                 N < 16 ? 3 : \
+                 N < 32 ? 4 : \
+                 N < 64 ? 5 : \
+		 N < 128 ? 6 : \
+		 N < 256 ? 7 : \
+		 N < 512 ? 8 : \
+		 N < 1024 ? 9 : \
+                 10)
+  
+  module binary_encoder
+    #(
+      parameter SIZE = 16
+      )
+      (
+       input [SIZE-1:0] in,
+       output [`LOG2(SIZE)-1:0] out
+       );
+   
+  genvar m,n;
+   
+   generate
+      // Loop enough times to represent the total number of input bits as an encoded value
+      for (m = 0; m <= `log2(SIZE-1); m = m + 1)  begin: expand_or_tree
+	 wire [SIZE-1:0] encoding;
+	 // Build enable mask by iterating through every input bit.
+	 for (n = 0; n < SIZE ; n = n + 1) begin: encode_this_bit
+	    assign encoding[n] = n[m];
+	 end
+	 // OR tree for this output bit with appropraite bits enabled.
+	 assign    out[m] = |(encoding & in);
+      end
+   endgenerate
+endmodule // binary_encoder
+
+   
+
+