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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
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