INTZBS = $10 ;INTERRUPT HANDLER
-POKMSK = $10 ;SYSTEM MASK FOR POKEY IRQ ENABLE
+POKMSK = $10 ;SYSTEM MASK FOR POKEY IRQ ENABLE (shadow of IRQEN)
BRKKEY = $11 ;BREAK KEY FLAG
RTCLOK = $12 ;REAL TIME CLOCK (IN 16 MSEC UNITS>
BUFADR = $15 ;INDIRECT BUFFER ADDRESS REGISTER