From 3433337eba97443b5da953f7b3e2186aca069a38 Mon Sep 17 00:00:00 2001
From: Aadi Desai <21363892+supleed2@users.noreply.github.com>
Date: Tue, 1 Dec 2020 23:04:43 +0000
Subject: [PATCH] Added Regfile

Missing partial/misaligned loads
---
 rtl/mips_cpu_harvard.v |  1 +
 rtl/mips_cpu_regfile.v | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100644 rtl/mips_cpu_regfile.v

diff --git a/rtl/mips_cpu_harvard.v b/rtl/mips_cpu_harvard.v
index 5997c0c..169361e 100644
--- a/rtl/mips_cpu_harvard.v
+++ b/rtl/mips_cpu_harvard.v
@@ -75,6 +75,7 @@ control control( //control flags block
 );
 
 regfile regfile(
+.clk(clk), //clock input for triggering write port
 .readreg1(rs),
 .readreg2(rt),
 .writereg(rd),
diff --git a/rtl/mips_cpu_regfile.v b/rtl/mips_cpu_regfile.v
new file mode 100644
index 0000000..8d69b64
--- /dev/null
+++ b/rtl/mips_cpu_regfile.v
@@ -0,0 +1,35 @@
+module regfile(
+input logic clk, //clock input for triggering write port
+input logic[4:0] readreg1, //read port 1 selector
+input logic[4:0] readreg2, //read port 2 selector
+input logic[4:0] writereg, //write port selector
+input logic[31:0] writedata, //write port input data
+input logic regwrite, //enable line for write port
+output logic[31:0] readdata1, //read port 1 output
+output logic[31:0] readdata2, //read port 2 output
+output logic[31:0] regv0 //debug output of $v0 or $2 (third register in file/ first register for returning function results)
+);
+
+reg[31:0] memory [31:0]; //32 register slots, 32-bits wide
+
+initial begin
+	integer i; //Initialise to zero by default
+    for (i = 0; i < 31; i++) begin
+        memory[i] = 0;
+    end
+end
+
+assign regv0 = memory[2]; //assigning debug $v0 line to $2 of memory
+
+always_comb begin
+	readdata1 = memory[readreg1]; //combinatorially output register value based on read port 1 selector
+	readdata2 = memory[readreg2]; //combinatorially output register value based on read port 2 selector
+end
+
+always_ff @(posedge clk) begin
+	if (regwrite) begin
+		memory[writereg] <= writedata;
+	end
+end
+
+endmodule : regfile
\ No newline at end of file