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[/] [potato/] [tags/] [v0.1/] [src/] [pp_utilities.vhd] - Rev 53
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-- The Potato Processor - A simple processor for FPGAs -- (c) Kristian Klomsten Skordal 2014 <kristian.skordal@wafflemail.net> -- Report bugs and issues on <http://opencores.org/project,potato,bugtracker> library ieee; use ieee.std_logic_1164.all; use work.pp_types.all; use work.pp_constants.all; package pp_utilities is --! Converts a boolean to an std_logic. function to_std_logic(input : in boolean) return std_logic; -- Checks if a number is 2^n: function is_pow2(input : in natural) return boolean; --! Calculates log2 with integers. function log2(input : in natural) return natural; -- Gets the value of the sel signals to the wishbone interconnect for the specified -- operand size and address. function wb_get_data_sel(size : in std_logic_vector(1 downto 0); address : in std_logic_vector) return std_logic_vector; end package pp_utilities; package body pp_utilities is function to_std_logic(input : in boolean) return std_logic is begin if input then return '1'; else return '0'; end if; end function to_std_logic; function is_pow2(input : in natural) return boolean is variable c : natural := 1; begin for i in 0 to 30 loop -- FIXME: Simulator complains about 2^31 being out of range! if input = i then return true; end if; c := c * 2; end loop; return false; end function is_pow2; function log2(input : in natural) return natural is variable retval : natural := 0; variable temp : natural := input; begin while temp > 1 loop retval := retval + 1; temp := temp / 2; end loop; return retval; end function log2; function wb_get_data_sel(size : in std_logic_vector(1 downto 0); address : in std_logic_vector) return std_logic_vector is begin case size is when b"01" => case address(1 downto 0) is when b"00" => return b"0001"; when b"01" => return b"0010"; when b"10" => return b"0100"; when b"11" => return b"1000"; when others => return b"0001"; end case; when b"10" => if address(1) = '0' then return b"0011"; else return b"1100"; end if; when others => return b"1111"; end case; end function wb_get_data_sel; end package body pp_utilities;
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