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[/] [System09/] [trunk/] [rtl/] [System09_Xess_XSA-3S1000/] [common.vhd] - Rev 193
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-------------------------------------------------------------------- -- Company : XESS Corp. -- Engineer : Dave Vanden Bout -- Creation Date : 05/17/2005 -- Copyright : 2005, XESS Corp -- Tool Versions : WebPACK 6.3.03i -- -- Description: -- Miscellaneous VHDL constants and functions -- -- Revision: -- 1.0.0 -- -- Additional Comments: -- 1.1.0: -- Added int_select() and real_select functions. -- 1.0.0: -- Initial release. -- -- License: -- This code can be freely distributed and modified as long as -- this header is not removed. -------------------------------------------------------------------- library IEEE; use IEEE.std_logic_1164.all; use IEEE.numeric_std.all; package common is constant YES : std_logic := '1'; constant NO : std_logic := '0'; constant HI : std_logic := '1'; constant LO : std_logic := '0'; constant ONE : std_logic := '1'; constant ZERO : std_logic := '0'; -- convert a Boolean to a std_logic function boolean2stdlogic(b : in boolean) return std_logic; -- find the base-2 logarithm of a number function log2(v : in natural) return natural; -- select one of two integers based on a Boolean function int_select(s : in boolean; a : in integer; b : in integer) return integer; -- select one of two reals based on a Boolean function real_select(s : in boolean; a : in real; b : in real) return real; end package common; library IEEE; use IEEE.std_logic_1164.all; use IEEE.numeric_std.all; package body common is -- convert a Boolean to a std_logic function boolean2stdlogic(b : in boolean) return std_logic is variable s : std_logic; begin if b then s := '1'; else s := '0'; end if; return s; end function boolean2stdlogic; -- find the base 2 logarithm of a number function log2(v : in natural) return natural is variable n : natural; variable logn : natural; begin n := 1; for i in 0 to 128 loop logn := i; exit when (n >= v); n := n * 2; end loop; return logn; end function log2; -- select one of two integers based on a Boolean function int_select(s : in boolean; a : in integer; b : in integer) return integer is begin if s then return a; else return b; end if; return a; end function int_select; -- select one of two reals based on a Boolean function real_select(s : in boolean; a : in real; b : in real) return real is begin if s then return a; else return b; end if; return a; end function real_select; end package body common;
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