Quick and dirty interrupt?

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By Edwin

Paragon (1182)

Аватар пользователя Edwin

07-10-2008, 00:24

How much faster would those vdp driven games be if they had written their own custon interrupt handler directly on 0x38 ?

I don't think they would have increased the memory requirements to 64KB for that.

By nikodr

Paladin (726)

Аватар пользователя nikodr

07-10-2008, 15:09

Edwin what i meant is that there is some precious time lost when there is the call to $fd9a and $fd9f through bios at the call to $38.

Yet despite that loss most of konami games are fast and do not suffer from it.Maybe the fact that the main loop of the game is in the interrupt routine has something to do with it?

Now if somebody could post an asm example that would feature sprite moving or horizontal scrolling through interrupt mode 2 ?
The flashing text example posted at karoshi site seems very good and uses im2 (though it does not have scrolling or moving of sprites).

By ducasp

Master (147)

Аватар пользователя ducasp

29-03-2019, 17:00

About the hook not working, there is a good chance that the code of your hook has been paged out, specially if it was in the lowest RAM bank (0-3FFF) as the MSX BIOS will be there most times hook is called.

P.s.: yeah, I know, older than dirty thread, but this shows up as one of the first hits for msx interrupt / hook, so hopefully this will help other people Tongue

By Wlcracks

Champion (321)

Аватар пользователя Wlcracks

29-03-2019, 17:27

wow 10 years

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