module RegFile(
input clk,
+ input Nrst,
input [3:0] read_0,
- output reg [31:0] rdata_0,
+ output wire [31:0] rdata_0,
input [3:0] read_1,
- output reg [31:0] rdata_1,
+ output wire [31:0] rdata_1,
input [3:0] read_2,
- output reg [31:0] rdata_2,
- output reg [31:0] spsr,
- input [3:0] write,
- input write_req,
+ output wire [31:0] rdata_2,
+ input [3:0] read_3,
+ output wire [31:0] rdata_3,
+ output wire [31:0] spsr,
+ input write,
+ input [3:0] write_reg,
input [31:0] write_data
);
reg [31:0] regfile [0:15];
+ integer i;
initial begin
- regfile[4'h0] = 32'h00000005;
- regfile[4'h1] = 32'h00000050;
- regfile[4'h2] = 32'h00000500;
- regfile[4'h3] = 32'h00005000;
- regfile[4'h4] = 32'h00050000;
- regfile[4'h5] = 32'h00500000;
- regfile[4'h6] = 32'h05000000;
- regfile[4'h7] = 32'h50000000;
- regfile[4'h8] = 32'hA0000000;
- regfile[4'h9] = 32'h0A000000;
- regfile[4'hA] = 32'h00A00000;
- regfile[4'hB] = 32'h000A0000;
- regfile[4'hC] = 32'h0000A000;
- regfile[4'hD] = 32'h00000A00;
- regfile[4'hE] = 32'h000000A0;
- regfile[4'hF] = 32'h00000000; /* Start off claiming we are in user mode. */
+ for (i = 0; i < 16; i = i + 1)
+ regfile[i] = 0;
end
- always @(*)
- begin
- if ((read_0 == write) && write_req)
- rdata_0 = write_data;
- else
- rdata_0 = regfile[read_0];
-
- if ((read_1 == write) && write_req)
- rdata_1 = write_data;
- else
- rdata_1 = regfile[read_1];
-
- if ((read_2 == write) && write_req)
- rdata_2 = write_data;
- else
- rdata_2 = regfile[read_2];
-
- spsr = regfile[4'hF];
- end
+ assign rdata_0 = ((read_0 == write_reg) && write) ? write_data : regfile[read_0];
+ assign rdata_1 = ((read_1 == write_reg) && write) ? write_data : regfile[read_1];
+ assign rdata_2 = ((read_2 == write_reg) && write) ? write_data : regfile[read_2];
+ assign rdata_3 = ((read_3 == write_reg) && write) ? write_data : regfile[read_3];
+ assign spsr = regfile[4'hF];
- always @(posedge clk)
- if (write_req)
- regfile[write] <= write_data;
+ always @(posedge clk or negedge Nrst)
+ if (!Nrst) begin
+ for (i = 0; i < 16; i = i + 1)
+ regfile[i] <= 0;
+ end else if (write)
+ regfile[write_reg] <= write_data;
endmodule