forth: add word "2DROP"

forth/dictionary.txt

@@ -100,6 +100,7 @@ DUP         a -- a a
 OVER        a b -- a b a
 ROT         a b c -- b c a
 SWAP        a b -- b a
+2DROP       a a --
 2DUP        a b -- a b a b
 2OVER       a b c d -- a b c d a b
 2SWAP       a b c d -- c d a b

forth/icore.fs

@@ -74,7 +74,7 @@
     _c DUP      ( a a )
     _c C@       ( a c )
     ( exit if null )
-    _c DUP NOT IF DROP DROP EXIT THEN
+    _c DUP NOT IF _c 2DROP EXIT THEN
     _c EMIT     ( a )
     1 _c +         ( a+1 )
     AGAIN
@@ -121,7 +121,7 @@
     UNTIL
     ( a this point, PS is: a WS )
     ( null-termination is already written )
-    DROP DROP
+    _c 2DROP
     [ JTBL 30 + @ LITN ]
 ;
 

forth/z80c.fs

@@ -69,6 +69,12 @@ CODE 2DUP
     HL PUSHqq,      ( B )
 ;CODE
 
+( a b -- )
+CODE 2DROP
+    HL POPqq,
+    HL POPqq,
+;CODE
+
 ( a b c d -- a b c d a b )
 
 CODE 2OVER