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Old 19 January 2008, 11:28   #1
BippyM
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Join Date: Nov 2001
Location: Derby, UK
Age: 45
Posts: 9,253
Custom MFM & Dos tracks

Hi guys

A quick query really

i'm looking at a game that uses both custom mfm and dos mfm tracks on the same disk, and i'm curious about the doio structure

now the filesize being passed to the iorequest structure is $00072800 bytes, and generally loads to $59e8 (though this changes as allocmem is used).

Now the game actually only loads about 3-4kb into ram and not 468992 bytes as passed to the iorequest structure!

Could this be due to the game hitting an unreadable mfm encoded track? or maybe i'm missing something!

I broke into the bootblock in a few places and I checked the iorequest offset myself so I know the size is right!

Also after the doio command the game then clears d0, clears $24 of the iorequest and then does a #cmd_nonstd before doing another doio.. what does this do?

Last edited by BippyM; 19 January 2008 at 23:01.
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