Home Page Forums MAME MAME Short delay....

Hi all,

Is there an easy way of inserting a short delay? I could setup an emu_timer, set a flag variable and then clear it in the timer's handler. then have a while (flag) do {} in the mainline.
But is there an easier way of doing this?

Cheers.

Phill.

That's not how MAME works. The while loop would prevent time from advancing. What are you actually trying to do?

Insert a delay between the CPU writing a value to a periperal and the value actually being written to the periperal.

e.g. :

Cheers.

Phill.

Create an emu_timer device and ->adjust() it to go off in whatever time you need.

You do whatever you want for you locally, of course, but I'm 98.5% certain there is no hardware in the nimbus to detect when a Dx value is written to the command register address and insert a bus delay in that case. So that wouldn't be accepted as-is, unless you have a way to prove there is such a thing.

As for the interrupt, the bios uses d0. That's a "gentle" interrupt we're probably running as too harsh, it's d8 that forces immediate stop. So I think we need to let the current action complete if it's a read or a write (not a search), which would probably do nicely with the rmnimbus.

The timing changes, otoh, why do you need them, what is happening in the bios?

Because my suggestions for altering the timing of the floppy code where 'rejected' and without them the machine's emulation doesn't work.

The Nimbus does inser 2 wait states in any transaction on the expansion bus (where the disk card is attached), However this only seems to have a significant effect on the force interrupt.

I had implemented the write changes in the wd_fdc code, which seemed to work for writes as suggested in the other thread. I did try with reads but couldn't get it to work.


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Not the bios but in the 'chipset' which as said above inserts wait states.

Cheers.

Phill.

The correct way to insert wait states is m_cpu->adjust_icount(-number_of_cycles). So if it's a 4 cycle wait, you'd adjust by -4.

Ahhh I did wonder about that, and looked through the code to see if there was an obvious way of doing that but didn't find it. I'll try that then.

Cheers.

Phill.