create decoder stage

1 files changed, 86 insertions, 0 deletions

diff --git a/decoder_stage.v b/decoder_stage.v
new file mode 100644
index 0000000..18ed195
--- /dev/null
+++ b/decoder_stage.v
@@ -0,0 +1,86 @@
+module decoder_stage (
+	input clk,
+	input en,
+
+	input [15:0] instr_in,
+	
+	output reg [3:0] aluOp_out,
+	output reg [2:0] aluReg1_out,
+	output reg [2:0] aluReg2_out,
+	output reg [1:0] aluOpSource1_out,		// ALU first operand: 0 = reg, 1 = memory read, 2 = imm8, 3 = PC
+	output reg [1:0] aluOpSource2_out,		// ALU second operand: 0 = reg, 1 = ~reg, 2 = PC, 3 = ???
+	output reg aluDest_out,					// 0 = reg, 1 = PC
+
+	output reg [2:0] regDest_out,
+	output reg regSetH_out,
+	output reg regSetL_out,
+	
+	output reg [2:0] regAddr_out,
+	output reg memReadB_out,
+	output reg memReadW_out,
+	output reg memWriteB_out,
+	output reg memWriteW_out,
+	
+	output reg [4:0] setRegCond_out,   // {should set when condition is true, Z doesn't matter, S doesn't matter, Z must be this, S must be this}
+	
+	output reg [15:0] imm_out
+);
+
+	wire [3:0] aluOp_next;
+	wire [2:0] aluReg1_next;
+	wire [2:0] aluReg2_next;
+	wire [1:0] aluOpSource1_next;
+	wire [1:0] aluOpSource2_next;
+	wire aluDest_next;
+	wire [2:0] regDest_next;
+	wire regSetH_next;
+	wire regSetL_next;
+	wire [2:0] regAddr_next;
+	wire memReadB_next;
+	wire memReadW_next;
+	wire memWriteB_next;
+	wire memWriteW_next;
+	wire [4:0] setRegCond_next;
+	wire [15:0] imm_next;
+
+	decoder decoder_inst (
+		.instr(instr_in),
+		.aluOp(aluOp_next),
+		.aluReg1(aluReg1_next),
+		.aluReg2(aluReg2_next),
+		.aluOpSource1(aluOpSource1_next),
+		.aluOpSource2(aluOpSource2_next),
+		.aluDest(aluDest_next),
+		.regDest(regDest_next),
+		.regSetH(regSetH_next),
+		.regSetL(regSetL_next),
+		.regAddr(regAddr_next),
+		.memReadB(memReadB_next),
+		.memReadW(memReadW_next),
+		.memWriteB(memWriteB_next),
+		.memWriteW(memWriteW_next),
+		.setRegCond(setRegCond_next),
+		.imm(imm_next)
+	);
+	
+	always @(posedge clk) begin
+		if(en) begin
+			aluOp_out <= aluOp_next;
+			aluReg1_out <= aluReg1_next;
+			aluReg2_out <= aluReg2_next;
+			aluOpSource1_out <= aluOpSource1_next;
+			aluOpSource2_out <= aluOpSource2_next;
+			aluDest_out <= aluDest_next;
+			regDest_out <= regDest_next;
+			regSetH_out <= regSetH_next;
+			regSetL_out <= regSetL_next;
+			regAddr_out <= regAddr_next;
+			memReadB_out <= memReadB_next;
+			memReadW_out <= memReadW_next;
+			memWriteB_out <= memWriteB_next;
+			memWriteW_out <= memWriteW_next;
+			setRegCond_out <= setRegCond_next;
+			imm_out <= imm_next;
+		end
+	end
+endmodule