It is not required, as long as the SYS is done in direct mode. Before 'READY.' is displayed, CBM BASIC does a CLI by itself. In a program however, interrupts would remain disabled.carlsson wrote:As you can see it gets significantly longer due to the more complex sound setup. I also added a CLI before RTS, which perhaps is not required.

The kernal would be better off including CLD in the first place.I don't know why CLD in the IRQ routine, but I'm sure Mike has a good reason for using it.

CBM BASIC for itself doesn't use decimal mode, so normally this is not going to make problems. But I had found a good use for decimal mode within MINIPAINT. When an interrupt occurs with decimal mode on, certain instructions in the IRQ will screw up as they don't expect it. I didn't want to "mask" the conversion routine within SEI/CLI as it takes quite long to execute, and decided to insert CLD in the IRQ as it had been altered anyway.