anchor.diff:  t: PACK$
     ALIGNED DUP >R OVER DUP 0 8 UM/MOD DROP - OVER + 0 SWAP !
     2DUP C! 1+ SWAP CMOVE R> ;
  +
  +\ Miscellaneous must-haves.
  +
  +t: 2*		1 LSHIFT ;
  +t: 1-		-1 + ;
   
   \ I/O device drivers.
   S" v-mgia.fs" included	( MGIA video )
  
positive.code: 
  \ pg 19
  
  t: NIP		SWAP DROP ;
  t: ?DUP		DUP IF DUP THEN ;
  t: ROT		>R SWAP R> SWAP ;
  t: 2DROP	DROP DROP ;
  
negative.code: \ pg 23 words
  
  t: 1+		1 + ;
  t: CELL-	-8 + ;
  t: CELL+	8 + ;
  t: CELLS	8 * ;
  