How can I OR every element in two dimensional array in one clock cycle? Verilog

Question

wire [a-1:0] array [b-1:0];

How can I OR the b array elements and get an a bits result in 1 clk? Thank you

Answer 1

Verilog ways:

reg [a-1:0] or_of_array;
integer i;
always @* begin
  or_of_array = array[0];
  for(i=1; i<b; i=i+1) begin
    or_of_array = or_of_array | array[i];
  end
end

SystemVerilog way:

logic [a-1:0] or_of_array;
always_comb begin
  or_of_array = 0;
  foreach(array[i]) begin
    or_of_array |= array[i];
  end
end

SystemVerilog also supports wire [a-1:0] wire_or_of_array = array.or(); but may not be supported by all synthesizer.

Answer 2

You can directly use a loop to or each element with previous element.

wire [a-1:0] op;

// Inside an always block
for (int i = 0; i < array.size(); i++)
  op = op | array[i];