25 Nov
2004
25 Nov
'04
9:07 p.m.
On Thu, 25 Nov 2004, Cameron Kaiser wrote:
This is almost on-topic now ^_^
Could you do a CALL -151 to achieve the same effect? I think that was the
clear screen for Integer BASIC (or maybe it was CALL -868 ... I forget).
CALL -151 was the command to return to the monitor from BASIC in the Apple
][ integer BASIC. I'm pretty sure location -151 did not map properly on
the Apple-1 since the monitor ROM was so completely different between the
I and ][.
CALL -868 was to clear the screen, but again that was on the Apple ][
which had a much expanded monitor ROM and some tools in ROM. The routine
at -868 actually stored ASCII 32 to all the locations in the memory mapped
screen, something the Apple-1 didn't have.
--
Sellam Ismail Vintage Computer Festival
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10 HOME
20 GOTO 10
Where do I send my mailing address? ;)
There was no HOME command in the original Apple-1 BASIC. The screen was
not memory-mapped. You would have to print enough carriage returns (16 I
believe) to push every line of text off the screen to clear it.