File size: 674 Bytes
78c261f | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | module stack_control(
input [1:0] instr_type,
input [4:0] opcode,
input stop_bit,
input [31:0] sp,
output reg push,
output reg pop,
output reg [31:0] next_sp
);
always @* begin
if (instr_type == 2'b10 && opcode == 5'b00001) begin // JAL
push = 1;
pop = 0;
next_sp = sp + 1; // push return address onto stack
end
else if(stop_bit) begin // end of function, get return address
push = 0;
pop = 1;
next_sp = sp - 1; // pop return address off stack
end
else begin
push = 0;
pop = 0;
next_sp = sp;
end
end
endmodule |