help - 11/34 console problem -- first LA output - test-drb@ccmp.vtda.org

7 Nov 2005

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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