blob: fca9b128ba7737d6891f8a99587ded60f8c1fc8d [file] [log] [blame]
module fsm (
clock,
reset,
req,
gnt
);
input clock,reset;
inout [1:0] req ;
output [1:0] gnt ;
wire clock,reset;
wire [1:0] req ;
reg [1:0] gnt ;
parameter SIZE = 3 ;
parameter IDLE = 3'b001,GNT0 = 3'b010,GNT1 = 3'b100,GNT2 = 3'b101,GNT3 = 3'b111;
reg [SIZE-1:0] state;
reg [SIZE-1:0] next_state;
always @ (posedge clock)
begin : FSM
if (reset == 1'b1) begin
state <= #1 IDLE;
gnt[0] <= 0;
gnt[1] <= 0;
end else
case(state)
IDLE : if (req[0] == 1'b1) begin
state <= #1 GNT0;
`ifndef BUG
gnt[0] <= 1;
`else
gnt[0] <= 1'bZ;
`endif
end else if (req[1] == 1'b1) begin
gnt[1] <= 1;
state <= #1 GNT0;
end else begin
state <= #1 IDLE;
end
GNT0 : if (gnt[1] == 1'b1) begin
state <= #1 GNT0;
end else begin
gnt[1] <= 0;
state <= #1 IDLE;
end
GNT1 : if (req[1] == 1'b1) begin
state <= #1 GNT2;
gnt[1] <= req[1];
end
GNT2 : if (gnt[0] == 1'b1) begin
state <= #1 GNT1;
gnt[1] <= req[1];
end
default : state <= #1 IDLE;
endcase
end
endmodule
module fsm2 (
clock,
reset,
req,
gnt
);
input clock,reset;
inout [1:0] req ;
output [1:0] gnt ;
wire clock,reset;
wire [1:0] req ;
reg [1:0] gnt ;
parameter SIZE = 3 ;
parameter IDLE = 3'b001,GNT0 = 3'b010,GNT1 = 3'b100,GNT2 = 3'b101,GNT3 = 3'b111;
reg [SIZE-1:0] state;
reg [SIZE-1:0] next_state;
always @ (posedge clock)
begin : FSM
if (reset == 1'b1) begin
state <= #1 IDLE;
gnt[0] <= 0;
gnt[1] <= 0;
end else
case(state)
IDLE : if (req[0] == 1'b1) begin
state <= #1 GNT0;
`ifndef BUG
gnt[0] <= 1;
`else
gnt[0] <= 1'bZ;
`endif
end else if (req[1] == 1'b1) begin
gnt[1] <= 1;
state <= #1 GNT0;
end else begin
state <= #1 IDLE;
end
GNT0 : if (gnt[1] == 1'b1) begin
state <= #1 GNT0;
end else begin
gnt[1] <= 0;
state <= #1 IDLE;
end
GNT1 : if (req[1] == 1'b1) begin
state <= #1 GNT2;
gnt[1] <= req[1];
end
GNT2 : if (gnt[0] == 1'b1) begin
state <= #1 GNT1;
gnt[1] <= req[1];
end
default : state <= #1 IDLE;
endcase
end
endmodule
module top (
input clk,
input rst,
input a,
input b,
output g0,
output g1
);
wire [1:0] g ;
wire [1:0] r ;
fsm u_fsm ( .clock(clk),
.reset(rst),
.req(r),
.gnt(g));
assign g0 = g[0];
assign g1 = g[1];
assign r[0] = a;
assign r[1] = b;
endmodule