Added unaligned access for instructions and data and fixed register file access

cpu/boot_code.txt

@@ -1,17 +1,17 @@
 // 0x00000000
-81C0
+05AA
-AA55
+55FE
+C0FE
+C0FE
+C005
+EF41
 FEC0
+0500
+05FE
+C081
+C1AA
+5505
 0000
-0000
+81C2
-0000
+BEEF
-0000
-0000
-0000
-0000
-0000
-0000
-0000
-0000
-0000
 0000

cpu/proc_state_def.v

@@ -1,13 +1,17 @@
-`define PROC_HALT_STATE		4'b0000
+`define PROC_HALT_STATE			4'b0000
 
 /*INSTRUCTION FETCH STATE*/
-`define PROC_IF_STATE_ENTRY	4'b0001
+`define PROC_IF_STATE_ENTRY		4'b0001
-`define PROC_IF_WRITE_CIR	4'b0010
+`define PROC_IF_WRITE_CIR		4'b0010
+`define PROC_IF_STATE_EXTRA_FETCH_SET	4'b0011
+`define PROC_IF_STATE_EXTRA_FETCH	4'b1111 /******/
 
 /*DECODE SATE*/
-`define PROC_DE_STATE_ENTRY	4'b0100
+`define PROC_DE_STATE_ENTRY		4'b0100
-`define PROC_DE_LOAD_16_PARAM	4'b0101
+`define PROC_DE_LOAD_16_PARAM		4'b0101
+`define PROC_DE_LOAD_16_EXTRA_FETCH_SET	4'b0110
+`define PROC_DE_LOAD_16_EXTRA_FETCH	4'b0111
 
 /*EXECUTE STATE*/
-`define PROC_EX_STATE_ENTRY	4'b1000
+`define PROC_EX_STATE_ENTRY		4'b1000
-`define PROC_EX_STATE_EXIT	4'b1001
+`define PROC_EX_STATE_EXIT		4'b1001

cpu/processor.v

@@ -22,6 +22,7 @@ reg [19:0] ProgCount;
 reg [15:0] CIR;
 reg [15:0] PARAM1;
 reg [15:0] PARAM2;
+reg unaligned_access;
 
 // Execution units
 reg [1:0] in1_sel;
@@ -38,6 +39,7 @@ always @(negedge reset) begin
 		reg_read=1;
 		reg_write=1;
 		reg_read_read=1;
+		unaligned_access=0;
 		ALU_OUT=1;
 		@(negedge clock);
 		@(posedge clock);
@@ -90,9 +92,18 @@ ADDER16 ADDER16_1(ADDER16_1A,ADDER16_1B,ALU_OUT,ADDER16_1O,ADDER16_1C);
 always @(negedge clock) begin
 	case(state)
 		`PROC_IF_WRITE_CIR:begin
-			CIR <= external_data_bus;
+			if(unaligned_access)begin
-			ProgCount=ProgCount+1;
+				CIR[15:8] <= external_data_bus[7:0];
-			state=`PROC_DE_STATE_ENTRY;
+				ProgCount=ProgCount+1;
+				state=`PROC_IF_STATE_EXTRA_FETCH_SET;
+			end else begin
+				CIR <= external_data_bus;
+				state=`PROC_DE_STATE_ENTRY;
+			end
+		end
+		`PROC_IF_STATE_EXTRA_FETCH:begin
+				CIR[7:0] <= external_data_bus[15:8];
+				state=`PROC_DE_STATE_ENTRY;
 		end
 		`PROC_EX_STATE_EXIT:begin
 			case(out_sel)
@@ -104,6 +115,10 @@ always @(negedge clock) begin
 			endcase
 			state=`PROC_IF_STATE_ENTRY;
 		end
+		`PROC_DE_LOAD_16_EXTRA_FETCH_SET:begin
+			external_address_bus = ProgCount;
+			state=`PROC_DE_LOAD_16_EXTRA_FETCH;
+		end
 	endcase
 end
 
@@ -123,14 +138,38 @@ always @(posedge clock) begin
 			ALU_OUT=1;
 			state=`PROC_IF_WRITE_CIR;
 		end
+		`PROC_IF_STATE_EXTRA_FETCH_SET:begin
+			external_address_bus <= ProgCount;
+			state=`PROC_IF_STATE_EXTRA_FETCH;
+		end
 		`PROC_DE_STATE_ENTRY:begin
-			external_address_bus <= ProgCount; /*Remenance from IF*/
 			case(CIR[15:10])
+				6'b000001 : begin
+					/* ADD, ... */
+					if ( CIR[9:9] == 0 )begin
+						/* Add Immediate to accumulator */
+						unaligned_access=~unaligned_access;
+						in1_sel=2'b00;
+						in2_sel=2'b01;
+						out_sel=2'b01;
+						reg_read_addr=3'b000;
+						reg_addr=3'b000;
+						reg_read_read=0;
+						ALU_OUT=0;
+						state=`PROC_DE_LOAD_16_PARAM;
+					end else begin
+						`invalid_instruction
+					end
+				end
 				6'b100000 : begin
 					/* ADD, ADC, SUB, SBB, CMP , AND, ... */
 					case (CIR[5:3])
 						3'b000 : begin
 							/* Add Immediate to register/memory */
+							if(unaligned_access==0)begin
+								ProgCount=ProgCount+1;
+								external_address_bus <= ProgCount;
+							end
 							in1_sel=2'b00;
 							in2_sel=2'b01;
 							out_sel=2'b01;
@@ -151,6 +190,10 @@ always @(posedge clock) begin
 						case (CIR[5:3])
 							3'b000 :begin
 								/* Increment Register or Memmory */
+								if(unaligned_access==0)begin
+									ProgCount=ProgCount+1;
+									external_address_bus <= ProgCount;
+								end
 								in1_sel=2'b00;
 								in2_sel=2'b01;
 								out_sel=2'b01;
@@ -175,15 +218,24 @@ always @(posedge clock) begin
 			endcase
 		end
 		`PROC_DE_LOAD_16_PARAM:begin
-			PARAM1 <= external_data_bus;
+			if(unaligned_access==1)begin
-			ProgCount=ProgCount+1;
+				PARAM1[15:8] = external_data_bus[7:0];
+				ProgCount=ProgCount+1;
+				state=`PROC_DE_LOAD_16_EXTRA_FETCH_SET;
+			end else begin
+				PARAM1 <= external_data_bus;
+				ProgCount=ProgCount+1;
+				state=`PROC_EX_STATE_ENTRY;
+			end
+		end
+		`PROC_DE_LOAD_16_EXTRA_FETCH:begin
+			PARAM1[7:0] = external_data_bus[15:8];
 			state=`PROC_EX_STATE_ENTRY;
 		end
 		`PROC_EX_STATE_ENTRY:begin
 			reg_data=ADDER16_1O;
 			state=`PROC_EX_STATE_EXIT;
 			EXCEPTION=0;
-
 		end
 	endcase
 end

cpu/registers.v

@@ -1,8 +1,7 @@
 module register_file ( input [2:0]addr1, inout [15:0]data1, input wire read1, input wire write1 ,input [2:0]addr2,output [15:0]data2,input wire read2);
 reg [15:0] registers [7:0];
-assign data2 = !read2 ? registers[0] : 'hz ;
+assign data2 = !read2 ? registers[addr2] : 'hz;
-//assign data2 = !read2 ? registers[addr2]: 'b1111000011110000;
+assign data1 = !read1 ? registers[addr1] : 'hz;
-assign data1 = !read1 ? registers[addr1]: 'hz;
 initial begin 
 	registers['b000]=0;
 	registers['b001]=0;

cpu/testbench.v

@@ -26,7 +26,7 @@ initial begin
 	reset = 0;
 	#(`CPU_SPEED) 
 	reset = 1;
-	#(`CPU_SPEED*30)
+	#(`CPU_SPEED*55)
 	//$writememh("register_dump.txt", registers);
 
 	#50 $finish;