# Data reuse
###### tags: `Digital IC Design`

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// data reuse
module example( sel, a, b, c, d, result );
input [3:0] a,b,c,d;
input sel;
output reg [7:0] result;

wire [3:0] tmp_0, tmp_1;
assign tmp_0 = ( sel )? a : b ;
assign tmp_1 = ( sel )? c : d ;
    
always @( * ) begin
    result = tmp_0 * tmp_1;
end
    
endmodule

module example( sel, a, b, c, d, result );
input [3:0] a,b,c,d;
input sel;
output reg [7:0] result;

always @( * ) begin
    if( sel ) result = a * b;
    else result = c * d;
end
    
endmodule

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|:---:|
|乘法器的面積遠大於 MUX，所以在設計電路的時候，要去想怎麼寫 data reuse|