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55acfed | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | /*
ALU module, which takes two operands of size 32-bits each and a 4-bit ALU_control as input.
Operation is performed on the basis of ALU_control value and output is 32-bit ALU_result.
If the ALU_result is zero, a ZERO FLAG is set.
*/
/*
ALU Control lines | Function
-----------------------------
0000 Bitwise-AND
0001 Bitwise-OR
0010 Add (A+B)
0100 Subtract (A-B)
1000 Set on less than
0011 Shift left logical
0101 Shift right logical
0110 Multiply
0111 Bitwise-XOR
*/
module ALU (
input [31:0] in1,in2,
input[3:0] alu_control,
output reg [31:0] alu_result,
output reg zero_flag
);
always @(*)
begin
// Operating based on control input
case(alu_control)
4'b0000: alu_result = in1&in2;
4'b0001: alu_result = in1|in2;
4'b0010: alu_result = in1+in2;
4'b0100: alu_result = in1-in2;
4'b1000: begin
if(in1<in2)
alu_result = 1;
else
alu_result = 0;
end
4'b0011: alu_result = in1<<in2;
4'b0101: alu_result = in1>>in2;
4'b0110: alu_result = in1*in2;
4'b0111: alu_result = in1^in2;
endcase
// Setting Zero_flag if ALU_result is zero
if (alu_result == 0)
zero_flag = 1'b1;
else
zero_flag = 1'b0;
end
endmodule |