percent.tdf

verilog编写的计算百分比模块

%
    ******************************************************************************
	*   This function is given as a free design, and may be freely distributed   *
	*   and modified, as long as this message remains intact.                    *
	*                                                                            *
	*   Written by Steven Groom ([e-mail])                       *
	*   Revision 1.0                                                             *
    ******************************************************************************
%

include "fn_divide";
include "fn_multiply";
parameters
(
	lpm_width=16
);
subdesign percent
(
	clock					:	input;		-- global clock input
	go_calc					:	input;		-- give a '1' on this signal for 1 period
											-- to start the state machine
	dataa[lpm_width-1..0]	:	input;		-- qty counted
	datab[lpm_width-1..0]	:	input;		-- total qty
	result[7..0]			:	output;		-- percentage (1 -> 100)
	no_calc					:	output;		-- this gives a '1' for 1 period to signal
											-- the end of the function
)
variable
	process					:	machine with states (idle,calc);

	fn_div					:	fn_divide with (lpm_width=lpm_width+7);
	fn_mult					:	fn_multiply with (lpm_width=lpm_width);
begin
	fn_div.clock=global(clock);
	fn_mult.clock=clock;
	process.clk=clock;
	fn_mult.dataa[]=dataa[];
	fn_mult.datab[]=100;
	fn_div.divnd[]=fn_mult.result[lpm_width+6..0];
	fn_div.divsr[]=(0,datab[]);
	fn_div.go_calc=fn_mult.no_calc;
	result[]=fn_div.quot[7..0];
	case process is
		when idle =>
			fn_mult.go_calc=go_calc;			
			if go_calc then		-- wait for start semaphore
				process=calc;
			end if;
		when calc =>
			if fn_div.no_calc then	-- wait for stop semaphore
				no_calc=vcc;
				process=idle;
			end if;
	end case;
end;