anchor.diff:  \ image memory.
   : UJ! ( displacement addr -- )
   	>R 0 S>UJ R@ IW@ $FFF AND OR R> IW! ;
  +
  +	\ As with UJ@, but for Bxx conditional branch instructions.
  +: SB@ ( addr -- displacement )
  +	IW@ 0 SB>S ;
  +
  +	\ As with UJ!, but for Bxx conditional branch instructions.
  +: SB! ( displacement addr -- )
  +	>R 0 S>SB R@ IW@ $01FFF07F AND OR R> IW! ;
   
   \ R, I, S, SB, U, and UJ, function like B, H, W, and D, above.  However, they
   \ place actual CPU instructions, and as such take additional parameters.
  
positive.code: 	\ instruction.
  : JAL> ( -- lc : "word" )
  	['] jalreloc (>) LC WORD+ ;
  
  	\ Apply a single fix-up.
  : fixup ( fx -- )
  
negative.code: 
  : SB, ( rs1 rs2 addr opmask -- )
  	4 ALIGN
  	>R LC WORD+ - R> S>SB (rs2) (rs1) W, ;
  
  : U, ( imm rd opmask -- )
  	4 ALIGN (rd) SWAP $FFFFF000 AND OR W, ;
  
  : UJ, ( addr rd opmask -- )
  	4 ALIGN (rd)
  	>R LC WORD+ - R> S>UJ W, ;
  
  \ Label Management.  Words of the form X> construct relocation records for
  \ as-yet-undefined symbols.  The different forms of relocation records exist
  