Apple-2gs-SW
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mrbuffer
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trying to display text via a loop, but will likely attempt using the toolbox stuff soon

This commit is contained in:
David Stancu 2018-01-26 21:25:23 -05:00
parent 9b5ffc265c
commit f338736ecc
1 changed files with 85 additions and 34 deletions
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119
src/main.S
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@ -2,62 +2,113 @@
typ $B3
dsk main.l
; ensure 16-bit mode (unnecessary?)
; ensure 16-bit mode (unnecessary?)
clc
xce
rep #$30
phk
plb
;;;;;
; we're going to need this
entrydp dw
phd
pla
sta entrydp
;;;;;;;;;
* sec
* clc
sep #$30 ; a, m, x half bank
lda #$00
pha
plb
; slide direct page up
lda #$0000
pha
pld
; toggle the softswitches; they don't take any values. some are only triggered
; by writes, $C054 can be triggered by a read
sta $C000 ; disable 80 column store?
sta $C00C ; disable 80 column hardware?!
sta $C050 ; set standard apple ii gfx mode
sta $C051 ; select text mode only. "only"?
lda $C054 ; select text page 1 (there are 2)
lda $C056 ; select "low res" graphics
; ok, we are done toggling switches, let's go make a string
rep #$30
phk
plb
lda entrydp
pha
pld
; the first byte of the str is its length, we'll use that for cmp
ldx #1
atxt str "O SHIT"
loopy nop
clc
cpx #4 ; compare with length, bail if too long
bcs outbrk
ldy atxt,x
lda #$00
pha
plb
lda #$0000
pha
pld
; direct acc for these?
sty $04,x
phk
plb
lda entrydp
pha
pld
*; toggle the softswitches; they don't take any values. some are only triggered
*; by writes, $C054 can be triggered by a read
sta $C000 ; disable 80 column store?
inx
sta $C00C ; disable 80 column hardware?!
sta $C050 ; set standard apple ii gfx mode
sta $C051 ; select text mode only. "only"?
lda $C054 ; select text page 1 (there are 2)
lda $C056 ; select "low res" graphics
jmp loopy
lda #"H"
sta $0400
lda #"e"
sta $0401
lda #"l"
sta $0402
lda #"l"
sta $0403
lda #"o"
sta $0404
lda #" "
sta $0405
lda #"W"
sta $0406
lda #"o"
sta $0407
lda #"r"
sta $0408
lda #"l"
sta $0409
lda #"d"
sta $040A
outbrk lda #37
brk
* lda #"H"
* sta $0400
* lda #"e"
* sta $0401
* lda #"l"
* sta $0402
* lda #"l"
* sta $0403
* lda #"o"
* sta $0404
* lda #" "
* sta $0405
* lda #"W"
* sta $0406
* lda #"o"
* sta $0407
* lda #"r"
* sta $0408
* lda #"l"
* sta $0409
* lda #"d"
* sta $040A
brk