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Atari Mega Archive 2
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Atari Mega Archive CD - Volume 2.iso
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8bit
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cislib_b
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scoff.asm
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Assembly Source File
|
1995-04-22
|
1KB
|
78 lines
;scoff - supercart off
;aycock, 9/87
;
;
*=$5555 ;out of the way
;
;
dosvec = $A
rtclok = $14
ramtop = $6A
statsav = $100
iccom = $342
icbal = $344
icbah = $345
icax1 = $34A
basicf = $3F8
cintlk = $3FA
crtstat = $AFFF
portb = $D301
ossoff = $D508
ciov = $E456
;
;
.byte $60 ;RTS for no re-entry
;
;
edev .byte "E:",$9B ;in a safe place
;
;
;
START ;THE ENTRY POINT...
;
ldx #0 ;close E:
lda #12
sta iccom
jsr ciov
;
lda rtclok ;wait for clock
CHK ; to change
cmp rtclok
beq CHK
;
sei ;disable interrupts and
lda crtstat ; the supercart
sta statsav
sta ossoff
lda #0
sta cintlk
;
lda #1 ;disable builtin basic
sta basicf
lda portb
ora #2
sta portb
;
lda #$C0 ;reset ramtop
sta ramtop
;
cli ;enable interrupts and
ldx #0 ; reopen E:
lda #3
sta iccom
lda #edev & $FF
sta icbal
lda #edev / $100
sta icbah
lda #12
sta icax1
jsr ciov
;
jmp (dosvec) ; back to Dos!
;
; INIT VECTOR
;
*=$2E2
;
.word START