TI-99/4A Floppies

[Chuck Guzis]

On 2 Oct 2007 at 19:05, Tony Duell wrote:

> And being a TMS9900-series CPU, aren't the registers in external RAM? I 
> guess the subroutine stack is too.. Which doesn't leave much space for 
> anything else.

Yup, 32 bytes/16 words at a toss.  And the usual subroutine linkage 
used a BLWP (Branch and Link Workspace Pointer or "Bullwhip") which 
set a completely new register frame for each subroutine.  So that 
didn't make for a lot of spare processor-local RAM.  Using 256 bytes 
of RAM at the late date of the 99/4A was screwy implmentation if 
there ever was one, though I suppose that some can think of some kind 
of advantage to this.

Cheers,
Chuck