Re: A86: Re: new emulator

To: assembly-86@lists.ticalc.org
Subject: Re: A86: Re: new emulator
From: rabidcow@juno.com
Date: Sat, 16 Oct 1999 02:52:17 -0700
Reply-To: assembly-86@lists.ticalc.org

ok, this is _getkey, and the value being written is the decoded key
value. (like kLeft)  i think that's supposed to be written to $c000, so
if that was $80 or the two high bits both select ram pages that would
work.  if this is from an early rom version, i'd say it's a bug.

-josh

On Thu, 23 Dec 1999 21:26:04 -0000 "Liyang Hu"
<liyang@liyang.freeserve.co.uk> writes:
>
>hmm... thanks for prompting me to look at my code again - after 
>messing with
>TI86Emu for a while, I managed to find the bit of code that's messing 
>my
>emulator up. It gets here straight after a keypress...
>Around 0x6960, ROM page 0x0a, we see this chunk of code:
>
>6957  IN A,($06)
>6959  PUSH AF
>695A  LD A,$80
>695C  OUT ($06),A
>695E  LD A,D
>695F  LD ($8000),A
>6952  POP AF
>
>that's definitely writing to the ROM... (unless bit 7 of port 6 
>actually
>does something... I was under the impression that this bit was 
>ignored, ne?)
>My emu crashes at 6960, just as it attempts the write.
>I can see TI86Emu going through this bit of code as well, but it 
>ignores the
>write, as far as I can tell. Now, my question is: WTF is it doing 
>writingto
>the ROM ?!?!?!? That's just going to make my code a lot more 
>complicated...
>(I'm not checking whether the mem is writable or not, for speed 
>reasons. I
>suppose I could always patch the ROM? What do you guys think?)
>
>> At what address in the ROM does it do this?  Some devices will
>> use writes to
>> ROM as hardware control registers, but the calc doesn't do this.
>>
>> > Should the ROM (program) be trying to write to the ROM (memory)
>> during its
>> > execution?
>
>sayoonara!
>--
> /*\-------------------------.   .----------------------------.
>|    Liyang Hu aka DenseBoy   \ /   __pikachu ICQ # 39391385   \
>|     http://www.nerv.cx/      |    <denseboy@41t4v¡5t4.n3t>    |
>+------------------------------+--------------------------------+
>|  When you say "I wrote a program that crashed Windows",       |
>|    people just stare at you blankly and say:                  |
>|      "Hey, I got those with the system, *for free*".          |
>|   -----------------------------------------------------------/
> \*/ /*  get my public key at http://www.nerv.cx/liyang.asc  */
>    /*   decode the l33t-speak in my address to email me!   */
>
>

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