Re: use of variable in zeropage on a CBM 8032

From: Anders Carlsson <*anders.carlsson_at_sfks.se*> Date: Fri, 15 Nov 2019 10:14:44 +0100 Message-ID: <cd3c3a7f-2af3-71e1-e947-ff7cee7cb7bf_at_sfks.se> · anders.carlsson_at_sfks.se

André Fachat wrote:

> If you don't use floating points you could use the FAC and other float
> registers (IIRC they are in zp, right?)

Yes, some possible locations with PET addresses (which are different 
from VIC/C64):

INDEX1: $1F - $20 (utility pointers)
INDEX2: $21 - $22
TEMPF3: $4B - $4F (temporary FLPT storage)
TEMPF1: $54 - $58
TEMPF2: $59 - $5D
FAC: $5E - $63
AFAC: $66 - $6B

As André wrote, it depends what the program does and which parts of the 
ROM it uses. If it doesn't do anything with the FAC, there should be 
plenty of space, in particular if you store the original ZP content and 
restore it on exit.

Best regards

Anders Carlsson