yosys/tests/xilinx/macc.v

38 lines
1005 B
Verilog

// Signed 40-bit streaming accumulator with 16-bit inputs
// File: HDL_Coding_Techniques/multipliers/multipliers4.v
//
module macc # (parameter SIZEIN = /*16*/7, SIZEOUT = 40)
(input clk, ce, sload,
input signed [SIZEIN-1:0] a, b,
output signed [SIZEOUT-1:0] accum_out);
// Declare registers for intermediate values
reg signed [SIZEIN-1:0] a_reg, b_reg;
reg sload_reg;
reg signed [2*SIZEIN:0] mult_reg;
reg signed [SIZEOUT-1:0] adder_out, old_result;
always @(adder_out or sload_reg) begin
//if (sload_reg)
//old_result <= 0;
//else
// 'sload' is now active (=low) and opens the accumulation loop.
// The accumulator takes the next multiplier output in
// the same cycle.
old_result <= adder_out;
a_reg <= a;
b_reg <= b;
end
always @(posedge clk)
//if (ce)
begin
mult_reg <= a_reg * b_reg;
sload_reg <= sload;
// Store accumulation result into a register
adder_out <= old_result + mult_reg;
end
// Output accumulation result
assign accum_out = adder_out;
endmodule // macc