decode_7segment.v

module decode_7segment (decimal, display);
  input [3:0] decimal;
  output [6:0] display;

/*
The binary encoded decimal digit is contained in decimal[0] to decimal[3].
Each element of display drives one segment of the output.
Boolean operation symbols:
   & = AND   e.g. (A & B)
   | = OR    e.g. (A | B)
   ~ = NOT   e.g. ( ~A)
*/

/* These are not correct...*/
assign display[0] = ~decimal[3] & (~decimal[2] | ~decimal[0]) & (decimal[2] 
| decimal[0]) & ~decimal[1];

assign display[1] = decimal[2] & (~decimal[0] |  ~decimal[1]) & (decimal[0] | decimal[1]);

assign display[2] = ~decimal[2] & decimal[1] & ~decimal[0];

assign display[3] = ~decimal[3] & (~decimal[2] | decimal[1] | ~decimal[0])
& (decimal[2] | ~decimal[1]) & (decimal[2]| decimal[0]) & (~decimal[1] | decimal[0]);

assign display[4] = (decimal[2] | decimal[0]) & (~decimal[1] | decimal[0]);

assign display[5] = ~decimal[3] & (~decimal[2] | decimal[1]) & 
(~decimal[2] | decimal[0]) & (decimal[1] | decimal[0]);

assign display[6] = ~decimal[3] & (~decimal[2] | decimal[1]) & 
(~decimal[2] | decimal[0]) & (decimal[2] | ~decimal[1]);
endmodule