Also,

Unless anyone objects, if your entry works with Bochs,
we will say that it works on real hardware. I would
rather not destroy my test machines UHCI hardware. Don't
think that it will, I would rather not take that chance.

Besides, the real test is the end of compo judgement time.

Sniper

P.S. Tapani, I have a 384 byte entry :-)
P.P.S. Boreal, I know you have a smaller entry. Where is it?

----- Original Message -----
From: "Benjamin David Lunt" <fys@...>
To: "Hugi-compo mailing list" <hugi-compo@yahoogroups.com>
Sent: Tuesday, June 23, 2009 6:57 PM
Subject: [hugi-compo] minor rule addition


> Hi everyone,
>
> With Tapani's small entry submission, I decided to work on my
> entry as well. As I was doing so, I came across what could
> be a discrepancy in the rules, so I have updated them a bit.
> (See the * in the first column and the note near the end of the
> rules)
>
> Details follow:
> When you set bit 9 in the UHCI port register, you are
> resetting the port. Then to clear the reset, you wait
> a minimum of 50ms and clear bit 9 in the port.
>
> However, the discrepancy in the rules comes from the fact
> that you could to the following:
>
> mov dx,io_base
> add dx,10h
> mov ax,(1<<9)
> out dx,ax
> call delay
> and ax,(~(1<<9))
> out dx,ax
>
> however, since the reset has taken place, during the delay,
> the hardware will set the bits in the port register to their
> default states and what not. If you simply write the old value
> back, only clearing bit 9 first, you may clear a bit that has
> been set due to the reset.
>
> Also, after you clear the reset bit, you must wait a short
> time for the reset to finish before you can set the enable
> bit. If you simply do:
>
> mov dx,io_base
> add dx,10h
> mov ax,(1<<9)
> out dx,ax
> call delay
> and ax,(~(1<<9))
> out dx,ax
> call delay
> or ax,(1<<2) ; <- ax may not be correct anymore
> out dx,ax
>
> ax won't contain the correct values. Now, on the UHCI, this
> may or may not be a problem, depending on how the hardware
> was made to handle RO and Reserved bits. However, it isn't
> good programming practice to do the above.
>
> So, I have made it a rule that you must read in the value,
> change the bit, then write it back as so:
>
> mov dx,io_base
> add dx,10h
> mov ax,(1<<9)
> out dx,ax
> call delay
> in ax,dx ; <---------
> and ax,(~(1<<9))
> out dx,ax
> call delay
> in ax,dx ; <---------
> or ax,(1<<2)
> out dx,ax
>
> It adds two instructions to your code.
>
> Sorry if this makes any problems with your current entry.
>
> Thanks,
> Sniper