dos33fsprogs/textmode/textscroll/move_bot.s
Vince Weaver ea240f158e text: moving text
didn't really work out as I was hoping
2021-04-23 20:44:06 -04:00

205 lines
3.4 KiB
ArmAsm

; TOKEN D734
; OUTDO (print char in A), calls COUT
; COUT calls ($0036)
CH = $24
CV = $25
BASL = $28
BASH = $29
CSWL = $36
SEEDL = $4E
FORPTR = $85
LOWTR = $9B
FACL = $9D
FACH = $9E
FRAME = $FA
XSAVE = $FB
STACKSAVE = $FC
YSAV = $FD
COUNT = $FE
DRAW_PAGE = $FF
PAGE0 = $C054
GETCHAR = $D72C ; loads (FAC),Y and increments FAC
TOKEN = $D734
HGR = $F3E2
SETTXT = $FB39
TABV = $FB5B ; store A in CV and call MON_VTAB
BASCALC = $FBC1
STORADV = $FBF0 ; store A at (BASL),CH, advancing CH, trash Y
MON_VTAB = $FC22 ; VTAB to CV
VTABZ = $FC24 ; VTAB to value in A
HOME = $FC58
CLREOL = $FC9C ; clear (BASL),CH to end of line
CLREOLZ = $FC9E ; clear (BASL),Y to end of line
WAIT = $FCA8 ;; delay 1/2(26+27A+5A^2) us
COUT = $FDED
COUT1 = $FDF0
COUTZ = $FDF6 ; cout but ignore inverse flag
ypos = $2000
xpos = $2100
textl = $2200
texth = $2300
which = $2400
move:
lda #<lowtr_fake
sta LOWTR
lda #<our_cout
sta CSWL
lda #>lowtr_fake
; lda #>our_cout ; should be same
sta LOWTR+1
sta CSWL+1
jsr HGR ; clear $2000 to 0
; A=0 at end
sta DRAW_PAGE
sta FORPTR ; used to trick LIST
jsr SETTXT ; set lo-res text mode
next_frame:
ldx #0
next_text:
lda xpos,X ; load next text xpos
bne not_new ; if not zero, continue
new_text:
jsr random8
and #$f
adc #$8
sta xpos,X ; get random X value 4...35
jsr random8
and #$f
sta ypos,X ; get random Y 0..15
jsr random8
ora #$80
sta which,X ; random token
not_new:
lda ypos,X
jsr BASCALC ; (basl) is now right
lda xpos,X
sta CH
; lda BASH
; clc
; adc DRAW_PAGE
; sta BASH
lda which,X
stx XSAVE ; save X
tsx
stx STACKSAVE ; save stack
jmp TOKEN ; call ROM token code
after_token:
ldx STACKSAVE ; restore stack
txs
ldx XSAVE ; restore X
dec xpos,X ; move left
inx ; move to next one
cpx #16
bne next_text
; X is 16 here
flip_pages:
; ldx #0
; lda DRAW_PAGE
; beq done_page
; inx
;done_page:
; ldy PAGE0-16,X ; set display page to PAGE1 or PAGE2
; eor #$4 ; flip draw page between $400/$800
; sta DRAW_PAGE
;===============
; clear screen
; ldx #24
clear_screen_loop:
; txa
; jsr BASCALC ; A is BASL at end
; lda BASH
; clc
; adc DRAW_PAGE
; sta BASH
; ldy #0
; jsr CLREOLZ
; dex
; bpl clear_screen_loop
; pause
; lda #100
; jsr WAIT
jmp next_frame
our_cout:
cmp #$8d ; list thinks end of line
bne regular_print
pla ; fake rts
pla
jmp after_token
regular_print:
sty YSAV
ldy CH
sta (BASL),Y
inc BASL
ldy YSAV
rts
;=============================
; random8
;=============================
; 8-bit 6502 Random Number Generator
; Linear feedback shift register PRNG by White Flame
; http://codebase64.org/doku.php?id=base:small_fast_8-bit_prng
random8:
lda SEEDL ; 2
beq doEor ; 2
asl ; 1
beq noEor ; if the input was $80, skip the EOR ; 2
bcc noEor ; 2
doEor: eor #$1d ; 2
noEor: sta SEEDL ; 2
rts
lowtr_fake:
.byte $00,$00 ; fake end to BASIC program
; want jump to live at $3F5
; currently at $383
; so want to load at $372
blah:
jmp move