help - 11/34 console problem -- first LA output

[Allison]

>
>Subject: Re: help - 11/34 console problem -- first LA output
>   From: "Chuck Guzis" <cclist at sydex.com>
>   Date: Mon, 07 Nov 2005 17:47:26 -0800
>     To: cctalk at classiccmp.org
>
>On 11/7/2005 at 11:57 PM ard at p850ug1.demon.co.uk wrote:
>
>>Be careful!. I have in the back of my mind the idea that the 8008 has an 
>>internal (8-ish level) return stack and doesn't use RAM for this. So you 
>>could still have RAM problems.
>
>Exactly--and they're 14 bits (not 16) wide--and overflow and underflow are
>not checked for.  It's sometimes easier just to think of it as 8 14-bit
>P-counters, with the CALL and RET simply incrementing and decrementing the
>pointer to the appropriate P-counter (with CALL performing a jump to load
>the current P-counter).
>
>Cheers,
>Chuck

Well save for wrap around.  The stack on 8008 is strictly address and
as already said 14bits (the 8008 only addresses 16k!!) and 8 levels deep.
It was a challenge programming it to figure out where you came from and
also not blow the stack.  Still it beat the design we had before it as
that was around 220 pcs of TTL sequential logic.

The interrupt/reset logic was pretty strange too.  



Allison