At 09:11 PM 7/20/99 +0200, you wrote:
>Like this:
>LD A,value
>DI
>OUT (#99),a
>LD A,register+128
>EI
>OUT (#99),a
>
>Keep in mind that when executing an EI the interrupts will be enabled after
>the next instruction. So this is the way to keep the interrupts disabled as
>short as possible, which is always preferred (although not required).
I just wondered... Does DI have this behaviour as well? If so, the example
above can execute incorrectly.
And remember that instructions like LDIR and OTIR are treated like "ultra
short loops" in terms of interrupts, meaning an interrupt can occur
"inside" an OTIR.
>> Is it legal to call 256 times #FD9F with interrupts disabled at VDP level?
>
>Absolutely. But it might re-enable the interrupt. You'll have to check that.
It might execute "EI". But unless there is some really weird routine
hanging on #FD9F, it won't enable interrupts at VDP level.
>But why do you need to keep the interrupts disabled???
Sony F700.
Bye,
Maarten
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