library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use work.math_pkg.all;

package gen_pkg is
	subtype alu_ops is std_logic_vector(2 downto 0);
	constant ALU_NOP : alu_ops := "000";
	constant ALU_SUB : alu_ops := "001";
	constant ALU_ADD : alu_ops := "010";
	constant ALU_MUL : alu_ops := "011";
	constant ALU_DIV : alu_ops := "100";
	constant ALU_DONE : alu_ops := "101";

	constant CBITS : integer := 32;
	subtype csigned is signed((CBITS-1) downto 0);
	subtype divinteger is unsigned(4 downto 0);
	-- integer ist 32bit (31bit + sign)
	subtype cinteger is integer;

	-- 50 zeilen * 71 zeichen * 2 (berechnung + ergebnis) = 7100 bytes
	constant hspalte_max : integer := 71;
	constant hzeile_max : integer := 50;
	constant H_RAM_SIZE : integer := 7100;
	constant H_RAM_WIDTH : integer := log2c(H_RAM_SIZE);
	subtype hspalte is std_logic_vector(6 downto 0);
	subtype hzeile is std_logic_vector(6 downto 0);
	subtype hbyte is std_logic_vector(7 downto 0);
	subtype hstring is string(1 to 72);
	subtype hstr_int is integer range 0 to 72;

	procedure icwait(signal clk_i : IN std_logic; cycles: natural);

	function ascii2sc (x : hbyte) return hbyte;
	function valid_char (x : hbyte) return boolean;

	-- http://www.marjorie.de/ps2/scancode-set2.htm
	constant SC_KP_0 : hbyte := x"70";
	constant SC_KP_1 : hbyte := x"69";
	constant SC_KP_2 : hbyte := x"72";
	constant SC_KP_3 : hbyte := x"7a";
	constant SC_KP_4 : hbyte := x"6b";
	constant SC_KP_5 : hbyte := x"73";
	constant SC_KP_6 : hbyte := x"74";
	constant SC_KP_7 : hbyte := x"6c";
	constant SC_KP_8 : hbyte := x"75";
	constant SC_KP_9 : hbyte := x"7d";

	constant SC_0 : hbyte := x"45";
	constant SC_1 : hbyte := x"16";
	constant SC_2 : hbyte := x"1e";
	constant SC_3 : hbyte := x"26";
	constant SC_4 : hbyte := x"25";
	constant SC_5 : hbyte := x"2e";
	constant SC_6 : hbyte := x"36";
	constant SC_7 : hbyte := x"3d";
	constant SC_8 : hbyte := x"3e";
	constant SC_9 : hbyte := x"46";

	constant SC_KP_PLUS : hbyte := x"79";
	constant SC_KP_MINUS : hbyte := x"7b";
	constant SC_KP_MUL : hbyte := x"7c";
	constant SC_KP_DIV : hbyte := x"4a"; -- inkl. 0xe0!

	-- fuer deutsches layout, alle anderen zeichen sind unguenstig belegt
	constant SC_PLUS : hbyte := x"5b";

	constant SC_ENTER : hbyte := x"5a";
	constant SC_BKSP : hbyte := x"66";
	constant SC_SPACE : hbyte := x"29";
end package gen_pkg;

package body gen_pkg is
	procedure icwait(signal clk_i : IN std_logic; cycles: Natural) is
	begin
		for i in 1 to cycles loop
			wait until clk_i= '0' and clk_i'event;
		end loop;
	end;

	function ascii2sc (x : hbyte) return hbyte is
		variable y : hbyte;
	begin
		case x is
			when x"30" => y := SC_KP_0;
			when x"31" => y := SC_KP_1;
			when x"32" => y := SC_KP_2;
			when x"33" => y := SC_KP_3;
			when x"34" => y := SC_KP_4;
			when x"35" => y := SC_KP_5;
			when x"36" => y := SC_KP_6;
			when x"37" => y := SC_KP_7;
			when x"38" => y := SC_KP_8;
			when x"39" => y := SC_KP_9;
			when x"2b" => y := SC_KP_PLUS;
			when x"2d" => y := SC_KP_MINUS;
			when x"2a" => y := SC_KP_MUL;
			when x"2f" => y := SC_KP_DIV;
			when x"20" => y := SC_SPACE;
			when x"1c" => y := SC_ENTER;
			when x"0e" => y := SC_BKSP;
			when others => y := x"41";
		end case;
		return y;
	end function;

	function valid_char (x : hbyte) return boolean is
		variable y : boolean;
	begin
		case x is
			when SC_KP_0 | SC_KP_1 | SC_KP_2 | SC_KP_3 |
				SC_KP_4 | SC_KP_5 | SC_KP_6 | SC_KP_7 |
				SC_KP_8 | SC_KP_9 | SC_KP_PLUS |
				SC_KP_MINUS | SC_KP_MUL |
				SC_KP_DIV | SC_SPACE |
				SC_BKSP | SC_ENTER =>
					y := true;
			when others => y := false;
		end case;
		return y;
	end function;
end package body gen_pkg;