collapseos/blk/300

lblnext BSET PC ORG @ 0x1b + ! ( next )
( This routine is jumped to at the end of every word. In it,
  we jump to current IP, but we also take care of increasing
  it by 2 before jumping. )
	( Before we continue: are stacks within bounds? )
    ( PS ) HL PS_ADDR LDddnn,
    SP SUBHLss,
    JRC, lblofl BWR ( abortUnderflow-B298 )
    ( RS ) IX PUSHqq, HL POPqq,
    DE RS_ADDR LDddnn,
    DE SUBHLss,
    JRC, lblofl BWR ( IX < RS_ADDR? abortUnderflow-B298 )
    E 0 IY+ LDrIXY,
    D 1 IY+ LDrIXY,
    IY INCss, IY INCss,
    ( continue to execute )