X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/5d9760a4dd32206c26c9f20fb995d29160bcbf71..45fa96c0a2fd6e490690cff69dd694a3dce3ab35:/Fetch.v

diff --git a/Fetch.v b/Fetch.v
new file mode 100644
index 0000000..0a18b31
--- /dev/null
+++ b/Fetch.v
@@ -0,0 +1,41 @@
+module Fetch(
+	input clk,
+	input Nrst,
+	
+	output wire [31:0] rd_addr,
+	output wire rd_req,
+	input rd_wait,
+	input [31:0] rd_data,
+	
+	input stall,
+	input jmp,
+	input [31:0] jmppc,
+	output wire bubble,
+	output wire [31:0] insn,
+	output reg [31:0] pc);
+
+	reg [31:0] prevpc;
+	initial
+		prevpc = 32'hFFFFFFFC;	/* ugh... the first pc we request will be this +4 */
+	always @(negedge Nrst)
+		prevpc <= 32'hFFFFFFFC;
+	
+	always @(*)
+		if (!Nrst)
+			pc = 32'hFFFFFFFC;
+		else if (stall)	/* don't change any internal state */
+			pc = prevpc;
+		else if (jmp)
+			pc = jmppc;
+		else
+			pc = prevpc + 32'h4;
+	
+	assign bubble = stall | rd_wait;
+	assign rd_addr = pc;
+	assign rd_req = !stall;
+	assign insn = rd_data;
+			
+	always @(posedge clk)
+		if (!rd_wait || !Nrst)
+			prevpc <= pc;
+endmodule