anchor.diff:  : lookup ( -- xt f )
   	BL WORD FIND ;
   
  -	\ Absolute Word forward reference prefix.  Leaves 0 on the stack for
  -	\ later consumption by W,.
  -: AW> ( -- 0 : "word" )
  +	\ Handle a generic forward reference.
  +: (>) ( xt -- : "word" )
   	>IN @
   	lookup IF
   		>BODY
  
positive.code: : UJ, ( addr rd opmask -- )
  	4 ALIGN (rd)
  	>R LC WORD+ - R>
  	OVER $100000 AND 11 LSHIFT OR
  	OVER $0007FE AND 20 LSHIFT OR
  	OVER $000800 AND 9 LSHIFT OR
  	SWAP $0FF000 AND OR W, ;
  
  
  \ Label Management.  Words of the form X> construct relocation records for
  \ as-yet-undefined symbols.  The different forms of relocation records exist
  
negative.code: 	lookup 0= ABORT" Label not defined"
  	DUP >BODY @ ['] val = NOT ABORT" Label expected"
  	EXECUTE gp0 @ - ;
  
  	\ Performs a single relocation for a UJ-format instruction.
  : fixup-jal ( a -- )
  	2 CELLS + @ >R
  	R@ UJ@
  	LC R@ WORD+ - +
  	R> UJ! ;
  
  : jalreloc ( a -- )
  	DUP HERE >R
  	CELL+ @ ,
  	['] fixup-jal ,
  	LC ,
  	gp0 @ ,
  	R> SWAP CELL+ ! ;
  
  	\ PC-relative forward reference prefix for JAL and other UJ-format
  	\ instructions.  Leaves LC+4 on the stack for consumption by the JAL
  	\ instruction.
  : JAL> ( -- lc : "word" )
  	['] jalreloc (>) LC WORD+ ;
  
  	\ Apply a single fix-up.
  : fixup ( fx -- )
  