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1984-04-29
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839b
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26 lines
This note is from Ward Christensen.
Here is some documentation which will be useful to VDM,
VTI, Flashwriter, or other memory-mapped or 16 line
video displays: It modifies the "P" command to scroll
15 lines instead of 23:
for 1.3 ED:
AC95 MVI M,F F=15, SETS NEW LINE COUNT
FOR 1.4 ED:
A161B LXI H,F
in either case, do as follows: Either SID or DDT ED.COM,
noting how high in memory it went (NEXT value) so you will
know how much to save later. Then do an L command at the
appropriate address (C95 or 161B), verifying that the
instruction there is either an MVI M or LXI H, with the
previous value (I believe it was 17H). Then patch in the
new instruction. Control-C to re-boot, then save nn EDVDM.COM.
Use this several times to be certain it is ok, then
ERA ED.COM and REN ED.COM=EDVDM.COM.