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	Commit message (Expand)	Author	Age	Files	Lines
*	satgen: Add support for dffe, sdff, sdffe, sdffce cells.	Marcelina Kościelnicka	2020-07-24	1	-0/+21

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module alu(
	input clk,
	input [7:0] A,
	input [7:0] B,
	input [3:0] operation,
	output reg [7:0] result,
	output reg CF,
	output reg ZF,
	output reg SF
);

	localparam ALU_OP_ADD /* verilator public_flat */ = 4'b0000;
	localparam ALU_OP_SUB /* verilator public_flat */ = 4'b0001;
	localparam ALU_OP_ADC /* verilator public_flat */ = 4'b0010;
	localparam ALU_OP_SBC /* verilator public_flat */ = 4'b0011;

	localparam ALU_OP_AND /* verilator public_flat */ = 4'b0100;
	localparam ALU_OP_OR  /* verilator public_flat */ = 4'b0101;
	localparam ALU_OP_NOT /* verilator public_flat */ = 4'b0110;
	localparam ALU_OP_XOR /* verilator public_flat */ = 4'b0111;

	localparam ALU_OP_SHL /* verilator public_flat */ = 4'b1000;
	localparam ALU_OP_SHR /* verilator public_flat */ = 4'b1001;
	localparam ALU_OP_SAL /* verilator public_flat */ = 4'b1010;
	localparam ALU_OP_SAR /* verilator public_flat */ = 4'b1011;

	localparam ALU_OP_ROL /* verilator public_flat */ = 4'b1100;
	localparam ALU_OP_ROR /* verilator public_flat */ = 4'b1101;
	localparam ALU_OP_RCL /* verilator public_flat */ = 4'b1110;
	localparam ALU_OP_RCR /* verilator public_flat */ = 4'b1111;

	reg [8:0] tmp;

	always @(posedge clk)
	begin
		case (operation)
			ALU_OP_ADD :
				tmp = A + B;
			ALU_OP_SUB :
				tmp = A - B;
			ALU_OP_ADC :
				tmp = A + B + { 7'b0000000, CF };
			ALU_OP_SBC :
				tmp = A - B - { 7'b0000000, CF };
			ALU_OP_AND :
				tmp = {1'b0, A & B };
			ALU_OP_OR :
				tmp = {1'b0, A | B };
			ALU_OP_NOT :
				tmp = {1'b0, ~B };
			ALU_OP_XOR :
				tmp = {1'b0, A ^ B};
			ALU_OP_SHL :
				tmp = { A[7], A[6:0], 1'b0};
			ALU_OP_SHR :
				tmp = { A[0], 1'b0, A[7:1]};
			ALU_OP_SAL :
				// Same as SHL
				tmp = { A[7], A[6:0], 1'b0};
			ALU_OP_SAR :
				tmp = { A[0], A[7], A[7:1]};
			ALU_OP_ROL :
				tmp = { A[7], A[6:0], A[7]};
			ALU_OP_ROR :
				tmp = { A[0], A[0], A[7:1]};
			ALU_OP_RCL :
				tmp = { A[7], A[6:0], CF};
			ALU_OP_RCR :
				tmp = { A[0], CF, A[7:1]};
		endcase

		CF <= tmp[8];
		ZF <= tmp[7:0] == 0;
		SF <= tmp[7];

		result <= tmp[7:0];
	end
endmodule