( BOOT DICT: There are only 3 words in the boot dict, but
  these words' offset need to be stable, so they're part of
  the "stable ABI" )
'E' A, 'X' A, 'I' A, 'T' A, 0 A,, ( prev ) 4 A, ( len )
H@ XCURRENT ! ( set current tip of dict, 0x42 )
    0 A, ( native )
    DX [BP] 0 MOVx[]+, BP DECx, BP DECx, ( popRS )
;CODE NOP,
CODE (br) ( 0x53 ) L2 BSET ( used in br? )
    DI DX MOVxx, DI [DI] MOVx[], DX DI ADDxx,
;CODE NOP, NOP,
CODE (?br) ( 0x67 )
    AX POPx, AX AX ORxx, JZ, L2 @ RPCs, ( False, branch )
    ( True, skip next 2 bytes and don't branch )
    L1 BSET ( loop will jump here ) DX INCx, DX INCx,
;CODE NOP, NOP, NOP, NOP, NOP,