verilog - How to convert two digit BCD into binary? -

i want make calculator based on fpga board(spartan 3). have following code

module bcd_converter( input [7:0] r, output reg [3:0] hundreds, output reg [3:0] tens, output reg [3:0] ones ); integer i; @ (r) begin     hundreds = 4'd0;     tens = 4'd0;     ones = 4'd0;     for(i=7;i>=0;i = i-1) begin         if(hundreds >= 5)                 hundreds = hundreds + 3;         if(tens >= 5)                 tens = tens + 3;         if(ones >= 5)                 ones = ones + 3;          hundreds = hundreds<<1;         hundreds[0] = tens[3];         tens = tens << 1;         tens[0] = ones[3];         ones = ones<<1;         ones[0] = r[i];       end end endmodule 

however, code provided conversion binary bcd. looking way reverse algorithm. there better way of converting bcd binary?

you decode each bcd digit binary separate case statements, , add results. example, hundreds case statement this:

case(hundreds)    4'd0 : hundreds_bin = 9'd0;    4'd1 : hundreds_bin = 9'd100;    4'd2 : hundreds_bin = 9'd200;    4'd3 : hundreds_bin = 9'd300; //..etc etc