Posted By
George
on 2019-05-17
04:44:22
 |  Access more hidden memory in BASIC
Hi all,
i want to ask some common known methods to access more, unused memory from BASIC when the Graphic Modes are activated. For example i remember using the cassette buffer or configuring memory layout...
Thanks in forward. |
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Posted By
KiCHY
on 2019-05-17
06:36:42
| Re: Access more hidden memory in BASIC
On Plus/4, in bitmap mode, $1000-$17FF is unused by BASIC, you can peek/poke/sys/etc there.
Another possibility, if you don't use text mode at all, $0800-$0FFF area is also free to use.
I'm sure there are more smaller areas under $0800 which you could utilize, I leave this sidequest to you, grabbing SVS Ultimate Map and find them  |
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Posted By
George
on 2019-05-17
18:19:20
| Re: Access more hidden memory in BASIC
Thank you Kichy.
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Posted By
MMS
on 2019-05-19
11:24:03
 | Re: Access more hidden memory in BASIC
I tried to make this homework in the past when I tried to squeeze the RS232 mouse driver into the zero page memory. (no success)
There are two main free areas below $800 you can really use (the character screen area is a good one from Kichy, maybe I will do the PETSCII shuttle, haha!):
$333-3F6: 191byte long Tape buffer
$65E-6EB: 141 byte long Speech module buffer
The rest is so fragmanted, it is almost useless.
Update: SVS is right, the Function key 127 byte long area also worth mentioning.
Nice TIE fighter !!! The Emperor would be proud of you, Darth George ! :-) |
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Posted By
SVS
on 2019-05-18
15:00:11
 | Re: Access more hidden memory in BASIC
Other free RAM areas are on:
$D0...$E8
$2F6...$2FD
$437...$472 Error stacks for Tape
$567...$5E6 if no Function key is set
$5E7...$5EB if no 1551 is present
$BE8...$BFF
$FE8...$FFF |
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Posted By
George
on 2019-05-18
19:07:19
| Re: Access more hidden memory in BASIC
Thank you MMS and SVS for your hints. Memory is really limited on a plus/4.
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Posted By
MMS
on 2019-05-19
17:59:33
| Re: Access more hidden memory in BASIC
now it seems you are preparing our small machine to make a new music clip for Kraftwerk?
(nice ones! are you aware, that one of the N/C pins on the expansion port in fact seems to be useable for RAM expansion? (RAM enable or what) (C) by gerliczer) |
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