Diskrom mirror differences between openMSX en BlueMSX

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Por Manuel

Ascended (18783)

Imagen del Manuel

07-02-2007, 19:35

What's essentially different about it?

By the way, in his modified diskROMs, Alwin Henseler also implemented _GETVER.... I wonder if it is coincidence that this was also in this eary VY 0010 diskROM.

Por zeilemaker54

Champion (341)

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07-02-2007, 22:06

Well, it is not essentially different. But later versions have a number of bugfixes. For example, the VY0010 version does not enable interrupts after a CALSLT. Also, the entry at 0401FH (DSKSTP stop drives of interface) is not supported (3 NOPs) AND the entry at 04029H (stop all drives) is not implemented (RET + 2 NOPs).
Because some code is different, it means also that some routines have a different entrypoint (05A11H-07396H area).

What's essentially different about it?

Por Kwik

Expert (127)

Imagen del Kwik

08-02-2007, 17:18

That is very interesting. I wonder, does the VY0010 diskrom search for a clockchip? I'm not sure if the VY-series is pre-msx2. If it is, then it probably doesn't know anything about the existance of chockchips...

Can you place the source on msxsyssrc?

Por zeilemaker54

Champion (341)

Imagen del zeilemaker54

08-02-2007, 20:06

I will, in time, place the source on msxsyssrc, but first I have to edit the source and test for correct assembling.
The dos kernel does check for a clockchip, so I suppose that a clockchip is optional for a MSX1 or diskinterface. Note that the dos kernel handles the absent of the clockchip, it does ask for the systemdate at startup!

@manuel or anyone: do you have rom dumps of other diskrom's of diskinterface cartridges ? And I do not mean build-in interfaces. A dump of a JVC interface would be very interesting...

Por Manuel

Ascended (18783)

Imagen del Manuel

09-02-2007, 19:53

Yeah, I'd also be interested in that Smile

Por Manuel

Ascended (18783)

Imagen del Manuel

10-02-2007, 22:42

If you want to visit Bas K. (Repair-Bas), you can ask him if you can make a dump Smile

Por Kwik

Expert (127)

Imagen del Kwik

12-02-2007, 13:38

... For example, the VY0010 version does not enable interrupts after a CALSLT.
What is the driver of a diskrom supposed to do regaring interrupts? I couldn't find anything about that in the documentation. Some drivers seem to enable the interrupt, while other do noting or disable it... What is the right behaviour? And what about the hooks ENAINT (FFD4) and DISINT (FFCD). Not al diskrom seems to use these hooks.

Por zeilemaker54

Champion (341)

Imagen del zeilemaker54

12-02-2007, 15:56

@Kwik: I was talking about the dos kernel itself, not the driver. The driver routines of the YV0010 is pretty standard (like other WD2793 drivers).

When the diskdriver is going to disable the interrupts (for a long time) it should call DISINT first and then do the DI. This is for example used by the RS232 interface to make clear to the other party to not send for a while
When the diskdriver is going to enable the interrupts again, it should first do the EI and then call ENAINT.

What is the driver of a diskrom supposed to do regaring interrupts? I couldn't find anything about that in the documentation. Some drivers seem to enable the interrupt, while other do noting or disable it... What is the right behaviour? And what about the hooks ENAINT (FFD4) and DISINT (FFCD). Not al diskrom seems to use these hooks.

Por Kwik

Expert (127)

Imagen del Kwik

12-02-2007, 16:26

Ok, but which does DSKCHG (8250 diskrom) enable the interrupt?

Por zeilemaker54

Champion (341)

Imagen del zeilemaker54

12-02-2007, 16:47

You mean the EI instruction at the start of the DSKCHG routine ? That one is needed because DSKCHG is called with a CALSLT, which disables the interrupts...
Ok, but which does DSKCHG (8250 diskrom) enable the interrupt?

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