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C02/include/atari/screen.a02
2018-11-07 00:11:09 -05:00

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;Screen Control Assembly Language Routines for Atari 400 & 800
;*** Incomplete - Copied from Oric-1 ***
; Display Colors
BLACK EQU $00 Black
RED EQU $00 Red
GREEN EQU $00 Green
YELLOW EQU $00 Yellow
BLUE EQU $00 Blue
MAGENT EQU $00 Magenta
CYAN EQU $00 Cyan
WHITE EQU $00 White
;ASCII Screen Control Characters
CHRBCK EQU $7E Backspace
CHRBEL EQU $FD Beep (Buzzer)
CHRCLR EQU $7D Clear Screen
CHRDEL EQU $FE Delete (Character)
CHRDWN EQU $1C Cursor Down
CHRFLS EQU $00 Flash On
CHRHOM EQU $00 Home (None)
CHRINS EQU $FF Insert (Character)
CHRLFT EQU $1E Cursor Left
CHRRGT EQU $1F Cursor Right
CHRRTN EQU $9B Return (End of Line)
CHRTAB EQU $7F Tab
CHRUP EQU $1B Cursor Up
;ATASCII Symbolic Characters
CHRBLK EQU $A0 Block
;ASCII Box Drawing Characters
BOXBLC EQU $0A Bottom Left Corner
BOXBRC EQU $03 Bottom Right Corner
BOXBCT EQU $18 Bottom to Cetter Tee
BOXCTR EQU $13 Center Cross
BOXHLN EQU $12 Horizontal Line
BOXLCT EQU $01 Left To Center T)
BOXRCT EQU $04 Right To Center T
BOXTLC EQU $11 Top Left Corner
BOXTRC EQU $05 Top Right Corner
BOXTCT EQU $17 Top to Center T
BOXVLN EQU $7C Vertical Line (|)
;Set Background Color
;Args: A = Atari Color Code
;Uses: TEMP0 - Temporary Storage
;Affects: A,C,N,Z
SCRBKG: AND $07 ;Strip High Bits
ORA $90 ;Convert to Control Character
JMP PRCHR ;Print Character and Return
;Set Text Color
;Args: A = Vic color code
;Affects: A,X,C,N,Z
SCRTXT: AND $07 ;Strip High Bits
ORA $80 ;Convert to Control Character
JMP PRCHR ;Print Character and Return
;Clear Screen
;Affects A,C,N,Z
SCRCLR: LDA #CHRCLR ;Load Clear Screen Character
JMP PRCHR ;Print it and Return
;Move Cursor Down
;Affects A,C,N,Z
SCRDWN: LDA #CHRDWN ;Load Cursor Down Character
JMP PRCHR ;Print it and Return
;Move Cursor To Home Position
;Affects A,C,N,Z
SCRHOM: LDA #0 ;Column 0
TAY ;Row 0
BEQ SRCMOV ;Move Cursor
;Move Cursor Left
;Affects A,C,N,Z
SCRLFT: LDA #CHRLFT ;Load Cursor Left Character
JMP PRCHR ;Print it and Return
;Move Cursor Right
;Affects A,C,N,Z
SCRRGT: LDA #CHRRGT ;Load Cursor Left Character
JMP PRCHR ;Print it and Return
;Move Cursor Up
;Affects A,C,N,Z
SCRUP: LDA #CHRUP ;Load Cursor Left Character
JMP PRCHR ;Print it and Return
;Move Cursor to Specified Coordinates
;Args: A = screen column (0 = top)
; Y = screen line (0 = left)
SCRMOV: RTS ;Not Yet Implemented
;Get Cursor Position
;Returns: A = current cursor column
; Y = current cursor row
SCRPOS: RTS ;Not Yet Implemented
;Get Screen Size
;Returns: A = width of screen in columns
; Y = height of screen in rows
SCRSIZ: RTS ;Not Yet Implemented