8086_documentation.md

@@ -51,8 +51,8 @@ Example instructions:
 
 |  Bytecode  |   AT&T Syntax   |                         meaning                            |
 | ---------- | --------------- | ---------------------------------------------------------- |
-|81 c0 aa 55 | add $0x55aa,%ax | add 0x55aa to register ax                                  |
+|81 c0 aa 55 | add $0x55aa,%ax | write 0x55aa to register ax                                |
-|03 06 aa 55 | add 0x55aa,%ax  | add the contents of memory locaton 0x55aa to register ax   |
+|03 06 aa 55 | add 0x55aa,%ax  | write the contents of memory locaton 0x55aa to register ax |
 |fe c0       | inc %al         | increment register al                                      |
 |ff c0       | inc %ax         | increment register ax                                      |
 |40          | inc %ax         | increment register ax                                      |

cpu/gtkwave_savefile.gtkw

@@ -1,34 +1,32 @@
 [*]
 [*] GTKWave Analyzer v3.3.104 (w)1999-2020 BSI
-[*] Thu Feb  9 14:44:08 2023
+[*] Wed Feb  8 23:43:14 2023
 [*]
 [dumpfile] "/home/user/UNI_DATA/COMS30046_2022_TB-2/projects/9086/cpu/test.lx2"
-[dumpfile_mtime] "Thu Feb  9 14:43:59 2023"
+[dumpfile_mtime] "Wed Feb  8 23:42:51 2023"
-[dumpfile_size] 757
+[dumpfile_size] 470
 [savefile] "/home/user/UNI_DATA/COMS30046_2022_TB-2/projects/9086/cpu/gtkwave_savefile.gtkw"
 [timestart] 0
-[size] 1630 1059
+[size] 1534 1059
 [pos] -1 -1
-*-22.795050 2010000 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
+*-20.795050 2883000 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
 [treeopen] tb.
 [sst_width] 221
 [signals_width] 293
 [sst_expanded] 1
 [sst_vpaned_height] 313
-@29
-tb.p.clock[0]
 @28
+tb.p.clock[0]
 tb.p.reset[0]
+tb.p.start[0]
+@29
+tb.p.state[2:0]
+@28
+tb.p.instruction_finished[0]
 @22
-tb.p.state[3:0]
 tb.p.external_address_bus[19:0]
 tb.p.external_data_bus[15:0]
-tb.p.CIR[15:0]
 @28
-tb.p.EXCEPTION[0]
+tb.p.read[0]
-tb.p.ADD_INST[0]
-tb.p.INC_INST[0]
-@22
-tb.p.PARAM1[15:0]
 [pattern_trace] 1
 [pattern_trace] 0

cpu/proc_state_def.v

@@ -1,12 +0,0 @@
-`define PROC_HALT_STATE		4'b0000
-
-/*INSTRUCTION FETCH STATE*/
-`define PROC_IF_STATE_ENTRY	4'b0001
-`define PROC_IF_WRITE_CIR	4'b0010
-
-/*DECODE SATE*/
-`define PROC_DE_STATE_ENTRY	4'b0100
-`define PROC_DE_LOAD_16_PARAM	4'b0101
-
-/*EXECUTE STATE*/
-`define PROC_EX_STATE_ENTRY	4'b1000

cpu/processor.v

@@ -1,5 +1,4 @@
 `timescale 1ns/1ps
-`include "proc_state_def.v"
 
 module clock_gen (input enable, output reg clk);
 
@@ -53,103 +52,53 @@ end
 endmodule
 
 
-module processor ( input clock, input reset , output reg [19:0] external_address_bus, inout [15:0] external_data_bus,output reg read, output reg write, output reg HALT);
+module processor ( input clock, input reset , output reg [19:0] external_address_bus, inout [15:0] external_data_bus,output reg read, output reg write);
 /* State */
-reg [3:0] state;
+reg [2:0] state;
+reg start=0;
 reg instruction_finished;
 
 /* Registers */
 reg [19:0] ProgCount;
-reg [15:0] CIR;
+reg [14:0] CIR;
-reg [15:0] PARAM1;
-reg [15:0] PARAM2;
 
 /* RESET LOGIC */
 always @(negedge reset) begin
 	if (reset==0) begin
 		@(posedge clock);
+		state=0;
 		ProgCount=0;//TODO: Reset Vector
-		ADD_INST=0;
+		#10
-		EXCEPTION=0;
+		start=1;
-		INC_INST=0;
-		HALT=0;
-		@(negedge clock);
-		@(posedge clock);
-		state=`PROC_IF_STATE_ENTRY;
 	end
 end
 
+/* CLOCK LOGIC */
+always @(posedge clock) begin
+	if(instruction_finished)
+		state =0;
+	else
+		if (clock && start==1)
+			state=state+1;
+end
+
+always @(state) begin
+	if (state==5)
+		instruction_finished=1;
+	else
+		instruction_finished=0;
+end
+
 /* Processor stages */
-reg ADD_INST,EXCEPTION,INC_INST;
+always @(state) begin
-
+	if (state=='b000) begin
-always @(negedge clock) begin
-	case(state)
-		`PROC_IF_WRITE_CIR:begin
-			CIR <= external_data_bus;
-			ProgCount=ProgCount+1;
-			state=`PROC_DE_STATE_ENTRY;
-		end
-	endcase
-end
-
-always @(posedge clock) begin
-	case(state)
-		`PROC_HALT_STATE:
-			HALT=1;
-		`PROC_IF_STATE_ENTRY:begin
 		external_address_bus <= ProgCount;
 		read <= 0;
 		write <= 1;
-			state=`PROC_IF_WRITE_CIR;
+	end else if ( state=='b001 ) begin
-		end
+		CIR <= external_data_bus;
-		`PROC_DE_STATE_ENTRY:begin
-			external_address_bus <= ProgCount; /*Remenance from IF*/
-			case(CIR[15:10])
-				6'b100000 : begin
-					case (CIR[5:3])
-						3'b000 :begin
-							ADD_INST=1;
-							state=`PROC_DE_LOAD_16_PARAM;
-						end
-						default:begin
-							EXCEPTION=1;
-							state=`PROC_EX_STATE_ENTRY;
-						end
-					endcase
-				end
-				6'b111111 : begin
-					if (CIR[9:9] == 1 ) begin
-						case (CIR[5:3])
-							3'b000 :begin
-								INC_INST=1;
-								state=`PROC_EX_STATE_ENTRY;
-							end
-							default:begin
-								EXCEPTION=1;
-								state=`PROC_EX_STATE_ENTRY;
-							end
-						endcase
-					end else begin
-						EXCEPTION=1;
-						state=`PROC_EX_STATE_ENTRY;
-					end
-				end
-				default:begin
-					EXCEPTION=1;
-					state=`PROC_EX_STATE_ENTRY;
-				end
-			endcase
-		end
-		`PROC_DE_LOAD_16_PARAM:begin
-			PARAM1 <= external_data_bus;
 		ProgCount=ProgCount+1;
-			state=`PROC_EX_STATE_ENTRY;
 	end
-		`PROC_EX_STATE_ENTRY:begin
-			EXCEPTION=0;ADD_INST=0;INC_INST=0;
-			state=`PROC_IF_STATE_ENTRY;
-		end
-	endcase
 end
 
 endmodule

cpu/testbench.v

@@ -4,9 +4,9 @@ reg reset;
 reg  clk_enable;
 wire [19:0]address_bus;
 wire [15:0]data_bus;
-wire rd,wr,romcs,HALT;
+wire rd,wr,romcs;
 
-processor p(clock,reset,address_bus,data_bus,rd,wr,HALT);
+processor p(clock,reset,address_bus,data_bus,rd,wr);
 rom bootrom(address_bus,data_bus,rd,romcs);
 
 `define CPU_SPEED 1000
@@ -22,7 +22,7 @@ initial begin
 
 	#($random%500)
 	reset = 0;
-	#(`CPU_SPEED) 
+	#(100) 
 	reset = 1;
 	#(`CPU_SPEED*30)