IRQL = $3FE
IRQH = $3FF
;--------------------------------------
SW_SLOTXROM_ENA = $C006
SW_SLOTXROM_DIS = $C007
SW_SLOTXROM_R = $C015 ; Active low
SW_SLOT3ROM_DIS = $C00A
SW_SLOT3ROM_ENA = $C00B
SW_SLOT3ROM_R = $C017 ; Active high