Bird: Hardware Design for CALL and RET instructions

module ilk_cpu(grounds, display, clk, pushbutton);

input     pushbutton; 
output  [3:0\] grounds;

output  \[6:0\] display;

input     clk; 





//memory map is defined here

localparam     BEGINMEM=12'h000,

        ENDMEM=12'h6ff,

        KEYPAD1=12'h900,

        KEYPAD2=12'ha00,

        SEVENSEG=12'hb00;



//  memory chip

reg     \[15:0\] memory \[0:511\]; 



// cpu's input-output pins

wire     \[15:0\] pc;

reg     \[15:0\] data\_out, data\_in;

reg     \[11:0\] address;

reg     memwt;



// input-output devices's pins

reg     \[15:0\] keypadregs \[1:0\];

reg     \[15:0\] ss7;