Re: Virtual serial drive

[Kevin <kevin@hackaday.com>]

On Tuesday, September 4, 2012 2:03:23 PM UTC-5, schmidtd wrote:
> On 9/4/2012 2:33 PM, BLuRry wrote:
> 
> > On Tuesday, September 4, 2012 12:40:01 PM UTC-5, schmidtd wrote:
> 
> >> On 9/4/2012 12:27 PM, David Schmidt wrote:
> 
> >>
> 
> >>> On 9/4/2012 11:59 AM, BLuRry wrote:
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> >>
> 
> >>>> On Tuesday, September 4, 2012 6:28:34 AM UTC-5, schmidtd wrote:
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> >>
> 
> >>>>> On 9/4/2012 4:46 AM, Ric wrote:> I try on my //c 255 rom but don't work
> 
> >>
> 
> >>>>> right.
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> >>
> 
> >>>>>
> 
> >>
> 
> >>>>>    > Should be rewrite serial card subroutine on file SERIAL.DRIVE
> 
> >>
> 
> >>>>>    > The command dos is Apple2VirtualDrive COM1 disk.hdv
> 
> >>
> 
> >>>>>
> 
> >>
> 
> >>>>> It won't work on a IIc because it is currently hard-coded to talk to the
> 
> >>
> 
> >>>>> GS serial hardware.  I've got the serial code isolated and bolted the
> 
> >>
> 
> >>>>> serial backend of ADTPro to it, and now it'll use whatever hardware is
> 
> >>
> 
> >>>>> supported by that.  But I still have to get the driver to attach to
> 
> >>
> 
> >>>>> ProDOS correctly - I'm reading the Beyond ProDOS book for that now.
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> >>
> 
> >>>>
> 
> >>
> 
> >>>> That's a pretty easy problem to fix!
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> >>
> 
> >>>
> 
> >>
> 
> >>> The 'problem' isn't the comms - I'm pretty solid on that - the problem
> 
> >>
> 
> >>> is cleanly interfacing to the P8 driver model.  I expect that a "hello
> 
> >>
> 
> >>> world" message from the driver's entry point that is fed to DEVADR21 (he
> 
> >>
> 
> >>> calls it DEV2S1) should produce that message when doing a CAT,S2,D1 -
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> >>
> 
> >>> but it crashes instead.
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> >>
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> >>>
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> >>
> 
> >>> The initialization code doesn't quite look complete to me, or at least
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> >>
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> >>> my translation to ca65 didn't come across quite right:
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> >>
> 
> >>>
> 
> >>
> 
> >>> ; ADD POINTER TO DRIVER
> 
> >>
> 
> >>>       LDA    #<DRIVER
> 
> >>
> 
> >>>       STA    DEV2S1
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> >>
> 
> >>>       LDA    #>DRIVER
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> >>
> 
> >>>       STA    DEV2S1+1
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> >>
> 
> >>> ; ADD TO DEVICE LIST
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> >>
> 
> >>>       INC    DEVCNT
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> >>
> 
> >>>       LDY    DEVCNT
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> >>
> 
> >>>       LDA    #$20 ; SLOT 2 DRIVE 1
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> >>
> 
> >>>       STA    DEVLST,Y
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> >>
> 
> >>>       RTS
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> >>
> 
> >>>
> 
> >>
> 
> >>> Where "DRIVER" is the entry point to the block driver command processor.
> 
> >>
> 
> >>>    Terence had only stored a value at DEV2S1+1, which can't be right...
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> >>
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> >>
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> >>
> 
> >> Ah, never mind.  I had it right after all.  I just needed to remember
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> >>
> 
> >> what environment I was in when the driver code is called... ROM is
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> >>
> 
> >> switched out, so calling COUT (among other things) was doomed.  ;-)
> 
> >
> 
> > I figured you knew how to do the com stuff, as it is far from your first rodeo.  I just posted that code for posterity in case anyone wanted to see the comparison.  Hooking into the prodos drivers can be tricky, I remember seeing others overwrite the disk routines to make room for alternate drivers but there's probably a much cleaner way to do it.  The advantage of overtaking the disk routines is that you have more room to add stuff like error checking and retry logic.
> 
> 
> 
> Right, the options seem to be either overwrite Disk II or ask P8 to 
> 
> allocate space.  I suppose that makes the case for one of each flavor...

I would personally go for the disk2, if the hdv file is hosted on a PC its really nothing to fire up cider press, add software and launch the server, and if you dont need the hard disk access, just dont load the driver from the boot disk.

just my opinion 

question though, since your using the serial magic of ADT, would that imply that one could use faster port speeds? ADT has no issue transferring disk images to my machine at 115Kbaud, but from basic 600 baud is kind of pushing it without the magic.

I thank you very much for your modifications to this driver, ASM is just something I get totally lost in, and really do appreciate your efforts.