alu: error flag setzen bei overflow/underflow bzw. bei division durch 0

[hwmod.git] / src / gen_pkg.vhd

diff --git a/src/gen_pkg.vhd b/src/gen_pkg.vhd
index 37667631f38d6d9da5f79ca1ff8b1b0ec045ef35..7f5e2dc30b387cbc02456b7276f66ac4fa648bd0 100644 (file)
--- a/src/gen_pkg.vhd
+++ b/src/gen_pkg.vhd
@@ -3,10 +3,44 @@ use ieee.std_logic_1164.all;
 use ieee.numeric_std.all;
 
 package gen_pkg is
-       type alu_ops is (NOP, SUB, ADD, MUL, DIV, DONE);
+       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);
-       --TODO: bei CBITS-1 gibts einen overflow :/
-       subtype cinteger is integer range -(2**(CBITS-2)) to ((2**(CBITS-2))-1);
+       -- integer ist 32bit (31bit + sign)
+       subtype cinteger is integer;
+
+       subtype hspalte is std_logic_vector(6 downto 0);
+       subtype hzeile is std_logic_vector(4 downto 0);
+       subtype hbyte is std_logic_vector(7 downto 0);
+       subtype hstring is string(1 to 71);
+
+       function find_msb(a : csigned) return natural;
+       procedure icwait(signal clk_i : IN std_logic; cycles: Natural);
 end package gen_pkg;
 
+package body gen_pkg is
+       function find_msb(a : csigned) return natural is
+               variable r : natural := 0;
+       begin
+               for i in (CBITS-1) downto 0 loop
+                       exit when a(i) = '1';
+                       r := r+1;
+               end loop;
+               return (CBITS - r);
+       end function find_msb;
+
+       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;
+end package body gen_pkg;
+