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; Initial load segment for the fnchat.exe executable. Sets MEMTOP and
; RAMTOP to $6A00, disables BASIC (on XL/XE), disables ANTIC DMA, then
; returns so the rest of the .xex continues to load.
; This is pretty weird: when loading fnchat.xex from MyDOS 4.50 or
; (apparently) Spartados X, a 0 byte gets written to our display
; list. It's up in the $BFxx area, which is to say, where the GR.0
; screen used by DOS lives... and somehow these DOSes are writing a
; 0 byte to the screen (a space) in the middle of loading the file.
; Setting SAVMSC to something else ($0600, here) avoids this.
*= $2000
memsetup
lda $d301 ; PORTB
ora #$02 ; disable BASIC (XL/XE only)
sta $d301
lda #$80
sta $6a ; RAMTOP
sta $02e6 ; MEMTOP high
lda #0
sta $02e5 ; MEMTOP low
sta $022f ; SDMCTL (turn off screen)
sta $58 ; SAVMSC
lda #$06
sta $59 ; SAVMSC+1
lda $14 ; RTCLOK+2
loop
cmp $14 ; wait until next frame
beq loop
rts
*= $02e2 ; INITAD
.word memsetup
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