Hi,
Laurens Holst <[EMAIL PROTECTED]> wrote:
> :> What might be an interesting spin-off is whether loading in page 1
> :> is legal or not.
> :
> :Absolutely legal. Supported by DOS1 (& DOS2 in other ways) with
> :various help-routines, and supported by every
> :(DOS1-compatible, used for SS/DS floppies) diskROM that I have come
> :across. If it wasn't legal to do this, I'm sure it wouldn't be so
> :generally supported, so sure this is okay.
>
> Ummm... reaction on a message posted some time ago:
>
> In Dos, loading in page 1 is ok. However, in Basic, loading in page 1 can,
> and will, corrupt the data. This is because the diskrom is swapped into page
> one.
>
> So, in Basic, you can't load into page 1.
In BASIC, you have the BASIC ROM in page 1, right? So how are you
gonna read data from disk in there?
If you have started a program from BASIC, and switched RAM into page
1, reading/writing data in there goes FINE, provided you indicate in
system variable (F342h) (DOS RAMslot for page 1) the RAM slot
currently selected in page 1.
Note for programmers: save this variable before changing it, set it,
do your thing, and restore as it was afterwards...
If you want to know how it works: get out a good debugger, and simply
trace a disk-call, and see what amount of trouble is gone through to
get the data where you wanted it...
As explained earlier, this all works a -bit- (?) different under
DOS2...
> This is because the diskrom is swapped into page one.
Happens just the same under DOS as well...
Greetings,
Alwin Henseler ([EMAIL PROTECTED])
http://huizen.dds.nl/~alwinh/msx (MSX Tech Doc page)
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