- added models

git-svn-id: http://moon:8086/svn/vhdl/trunk@1290 cc03376c-175c-47c8-b038-4cd826a8556b

lib/models/memory/sdram/mt48lc32m4a2/mti_pkg.vhd

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+--*****************************************************************************
+--
+-- Micron Semiconductor Products, Inc.
+--
+-- Copyright 1997, Micron Semiconductor Products, Inc.
+-- All rights reserved.
+--
+--*****************************************************************************
+
+LIBRARY work;
+LIBRARY ieee;
+USE ieee.std_logic_1164.ALL;
+
+PACKAGE mti_pkg IS
+
+    FUNCTION  TO_INTEGER  (input : STD_LOGIC) RETURN INTEGER;
+    FUNCTION  TO_INTEGER  (input : BIT_VECTOR) RETURN INTEGER;
+    FUNCTION  TO_INTEGER (input : STD_LOGIC_VECTOR) RETURN INTEGER;
+    PROCEDURE TO_BITVECTOR  (VARIABLE input : IN INTEGER; VARIABLE output : OUT BIT_VECTOR);
+
+END mti_pkg;
+
+PACKAGE BODY mti_pkg IS
+
+    -- Convert BIT to INTEGER
+    FUNCTION  TO_INTEGER (input : STD_LOGIC) RETURN INTEGER IS
+    VARIABLE result : INTEGER := 0;
+    VARIABLE weight : INTEGER := 1;
+    BEGIN
+        IF input = '1' THEN
+            result := weight;
+        ELSE
+            result := 0;                                            -- if unknowns, default to logic 0
+        END IF;
+        RETURN result;
+    END TO_INTEGER;
+
+    -- Convert BIT_VECTOR to INTEGER
+    FUNCTION  TO_INTEGER (input : BIT_VECTOR) RETURN INTEGER IS
+    VARIABLE result : INTEGER := 0;
+    VARIABLE weight : INTEGER := 1;
+    BEGIN
+        FOR i IN input'LOW TO input'HIGH LOOP
+            IF input(i) = '1' THEN
+                result := result + weight;
+            ELSE
+                result := result + 0;                               -- if unknowns, default to logic 0
+            END IF;
+            weight := weight * 2;
+        END LOOP;
+        RETURN result;
+    END TO_INTEGER;
+
+    -- Convert STD_LOGIC_VECTOR to INTEGER
+    FUNCTION  TO_INTEGER (input : STD_LOGIC_VECTOR) RETURN INTEGER IS
+    VARIABLE result : INTEGER := 0;
+    VARIABLE weight : INTEGER := 1;
+    BEGIN
+        FOR i IN input'LOW TO input'HIGH LOOP
+            IF input(i) = '1' THEN
+                result := result + weight;
+            ELSE
+                result := result + 0;                               -- if unknowns, default to logic 0
+            END IF;
+            weight := weight * 2;
+        END LOOP;
+        RETURN result;
+    END TO_INTEGER;
+
+    -- Conver integer to bit_vector
+    PROCEDURE  TO_BITVECTOR (VARIABLE input : IN INTEGER; VARIABLE output : OUT BIT_VECTOR) IS
+    VARIABLE work,offset,outputlen,j : INTEGER := 0;
+    BEGIN
+        --length of vector
+        IF output'LENGTH > 32 THEN
+            outputlen := 32;
+            offset := output'LENGTH - 32;
+            IF input >= 0 THEN
+                FOR i IN offset-1 DOWNTO 0 LOOP
+                    output(output'HIGH - i) := '0';
+                END LOOP;
+            ELSE
+                FOR i IN offset-1 DOWNTO 0 LOOP
+                    output(output'HIGH - i) := '1';
+                END LOOP;
+            END IF;
+        ELSE
+            outputlen := output'LENGTH;
+        END IF;
+        --positive value
+        IF (input >= 0) THEN
+            work := input;
+            j := outputlen - 1;
+            FOR i IN 1 to 32 LOOP
+                IF j >= 0 then
+                    IF (work MOD 2) = 0 THEN 
+                        output(output'HIGH-j-offset) := '0';
+                    ELSE
+                        output(output'HIGH-j-offset) := '1';
+                    END IF;
+                END IF;
+                work := work / 2;
+                j := j - 1;
+            END LOOP;
+            IF outputlen = 32 THEN
+                output(output'HIGH) := '0';
+            END IF;
+        --negative value
+        ELSE
+            work := (-input) - 1;
+            j := outputlen - 1;
+            FOR i IN 1 TO 32 LOOP
+                IF j>= 0 THEN
+                    IF (work MOD 2) = 0 THEN 
+                        output(output'HIGH-j-offset) := '1';
+                    ELSE
+                        output(output'HIGH-j-offset) := '0';
+                    END IF;
+                END IF;    
+                work := work / 2;
+                j := j - 1;
+            END LOOP;
+            IF outputlen = 32 THEN
+                output(output'HIGH) := '1';
+            END IF;
+        END IF;
+    END TO_BITVECTOR;
+
+END mti_pkg;