From: Joshua Wise <joshua@rebirth.joshuawise.com>
Date: Fri, 9 Jan 2009 09:01:19 +0000 (-0500)
Subject: Writeback: add
X-Git-Url: http://git.joshuawise.com/firearm.git/commitdiff_plain/331c3b8d1138a3a2982a1b15251bd4cb16003e33?hp=-c

Writeback: add
---

331c3b8d1138a3a2982a1b15251bd4cb16003e33
diff --git a/Writeback.v b/Writeback.v
new file mode 100644
index 0000000..b0e69cf
--- /dev/null
+++ b/Writeback.v
@@ -0,0 +1,63 @@
+module Writeback(
+	input clk,
+	
+	input inbubble,
+	
+	input write_reg,
+	input [3:0] write_num,
+	input [31:0] write_data,
+	
+	input [31:0] cpsr,
+	input [31:0] spsr,
+	
+	output reg regfile_write,
+	output reg [3:0] regfile_write_reg,
+	output reg [31:0] regfile_write_data,
+	
+	output reg [31:0] outcpsr,
+	output reg [31:0] outspsr,
+	
+	output reg jmp,
+	output reg [31:0] jmppc);
+	
+	reg [31:0] last_outcpsr = 0, last_outspsr = 0;
+	
+	always @(*)
+		if (inbubble)
+			outcpsr = last_outcpsr;
+		else
+			outcpsr = cpsr;
+	
+	always @(*)
+		if (inbubble)
+			outspsr = last_outspsr;
+		else
+			outspsr = spsr;
+	
+	always @(*)
+	begin
+		regfile_write = 0;
+		regfile_write_reg = 4'hx;
+		regfile_write_data = 32'hxxxxxxxx;
+		jmp = 0;
+		jmppc = 32'h00000000;
+		if (!inbubble)
+		begin
+			if (write_reg && (write_num != 15))
+			begin
+				regfile_write = 1;
+				regfile_write_reg = write_num;
+				regfile_write_data = write_data;
+			end else if (write_reg && (write_num == 15)) begin
+				jmp = 1;
+				jmppc = write_data;
+			end
+		end
+	end
+	
+	always @(posedge clk)
+	begin
+		last_outspsr <= outspsr;
+		last_outcpsr <= outcpsr;
+	end
+endmodule