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Is there a SYS to perform a run/stop-restore?
Posted: Sat May 29, 2004 5:56 am
by Boray
Is there a SYS to perform a run/stop-restore? There doesn't seem to be a RESTORE button on the vic20-emulator on Amiga, so I would need a SYS to do the same thing as the button combination. (By first pressing break and then typing in the SYS manually)... Anyone?
/Anders
Posted: Tue Jun 01, 2004 7:59 am
by carlsson
In theory, I believe the BRK instruction (op-code 00) will cause a NMI interrupt just like pressing the RESTORE key will do. SYS 65234 should cause a Basic Warm Start, which occurs when a BRK is reached.
See also the document
http://www.ftp.funet.fi/pub/cbm/documen ... c20rom.doc and similar ones (C64 may do too) for other hints.
SYS 58471 supposedly warm-starts Basic without clearing the screen like the other one above, but you really want it to appear like you hit RUN/STOP + RESTORE?
Posted: Tue Jun 01, 2004 8:06 am
by carlsson
More in detail, SYS 65234 will restore Kernal vectors (IRQ etc at $0314), then initialise (prepare?) I/O and initialize (restore?) I/O and finally call the Basic routine at 58471 to restart Basic.
Posted: Wed Jun 02, 2004 5:07 am
by Boray
sys65234 works great! Thanks!!! And it's an easy number to remember too! Thanks!
/Anders