Posted By
neils
on 2022-01-26
09:29:07
|  Re: Change screen address
Thanks for your answer Csabo.
I was hoping that I could do something similar to this C64 example:
lda $d018
and #%11110000
ora #%00100000
sta $d018 ; Change screen address from $0400 to $0800
lda #$08
sta $0288 ; Update KERNAL screen pointer
ora #$80
tay
lda #0
tax
.loop
sty $D9,x ;Update pointers to screen lines
clc
adc #$28
bcc .skip
iny
.skip
inx
cpx #$1a
bne .loop
lda #$ff
sta $D9,x
From this point on, the screen editor will use the new location. So my understanding is that the Plus/4 can't do this, as these pointers are hardwired in KERNAL. Too bad 
Where can I find a commented disassembly of the Plus/4 KERNAL? Maybe there's a workaround?
PS. It isn't for a game. I'm trying to implement XC=BASIC's commands on the Plus/4 and I'm failing to implement this command: https://xc-basic.net/doku.php?id=v3:screen
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