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