5 files changed, 117 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore
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--- /dev/null
+++ b/.gitignore
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+*.swp
+.DS_Store
diff --git a/ec413-lab6.pdf b/ec413-lab6.pdf
new file mode 100644
index 0000000..d791ddf
--- /dev/null
+++ b/ec413-lab6.pdf
diff --git a/fsm.v b/fsm.v
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+++ b/fsm.v
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+`timescale 1ns / 1ps
+// FSM module
+//
+// drives the data path through multiple cycles
+
+module fsm(
+  output [3:0] state,
+  input [2:0] instrtype,
+  input rst,
+  input clk
+);
+
+`include "params.v"
+
+reg [3:0] state, nextstate;
+
+always @(*) begin
+  if (rst) begin
+    nextstate = FETCH;
+  end else begin
+    case (state)
+      FETCH: nextstate = DECODE;
+      DECODE: if (instrtype == IINSTR || instrtype == RINSTR)
+                nextstate = ALUOP;
+              else if (instrtype == MEMRINSTR || instrtype == MEMWINSTR)
+                nextstate = MEMCALC;
+              else if (instrtype == BRINSTR)
+                nextstate = BRANCH;
+              else if (instrtype == JINSTR)
+                nextstate = JUMP;
+      MEMCALC: if (instrtype == MEMWINSTR)
+                 nextstate = MEMWRITE;
+               else if (instrtype == MEMRINSTR)
+                  nextstate = MEMREAD;
+      MEMWRITE: nextstate = FETCH;
+      MEMREAD: nextstate = MEMSTORE;
+      MEMSTORE: nextstate <= FETCH;
+      ALUOP: nextstate = ALUSTORE;
+      ALUSTORE: nextstate = FETCH;
+      BRANCH: nextstate = FETCH;
+      JUMP: nextstate = FETCH;
+    endcase
+  end
+end
+
+always @(posedge clk or posedge rst) begin
+  state <= rst ? FETCH : nextstate;
+end
+
+endmodule
+
diff --git a/params.v b/params.v
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+++ b/params.v
@@ -0,0 +1,22 @@
+
+// These are all the types of instructions we have,
+// each represents a path through the FSM
+parameter RINSTR = 3'd0; // R-type ALU instruction
+parameter IINSTR = 3'd1; // I-type ALU instruction
+parameter MEMRINSTR = 3'd2; // memory read
+parameter MEMWINSTR = 3'd3; // memory write
+parameter BRINSTR = 3'd4; // branch
+parameter JINSTR = 3'd5; //jump
+
+// and these are nice names for the various states
+parameter FETCH    = 4'd0;
+parameter DECODE   = 4'd1;
+parameter MEMCALC  = 4'd2;
+parameter MEMWRITE = 4'd3;
+parameter MEMREAD  = 4'd4;
+parameter MEMSTORE = 4'd5;
+parameter ALUOP    = 4'd6;
+parameter ALUSTORE = 4'd7;
+parameter BRANCH   = 4'd8;
+parameter JUMP     = 4'd9;
+
diff --git a/test_fsm.v b/test_fsm.v
new file mode 100644
index 0000000..0f86ef4
--- /dev/null
+++ b/test_fsm.v
@@ -0,0 +1,42 @@
+`timescale 1ns / 1ps
+
+module test_fsm;
+
+`include "params.v"
+
+reg clk, rst;
+reg [2:0] itype;
+wire [3:0] state;
+
+fsm uut(
+  .state(state),
+  .instrtype(itype),
+  .clk(clk),
+  .rst(rst)
+);
+
+initial begin
+  //$dumpfile("test_fsm.vcd");
+  //$dumpvars(0, uut);
+  clk = 0; rst = 0; itype = RINSTR;
+  #100;
+  #19; rst = 1; #1; rst = 0;
+  itype = RINSTR;
+  #19; rst = 1; #1; rst = 0;
+  itype = MEMRINSTR;
+  #19; rst = 1; #1; rst = 0;
+  itype = MEMWINSTR;
+  #19; rst = 1; #1; rst = 0;
+  itype = BRINSTR;
+  #19; rst = 1; #1; rst = 0;
+  itype = JINSTR;
+  #19; rst = 1; #1; rst = 0;
+  #100;
+  //$finish;
+end
+
+always begin
+  clk = ~clk; #1;
+end
+
+endmodule