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447 lines
14 KiB
ArmAsm
447 lines
14 KiB
ArmAsm
;
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; Graphics driver for the 280x192x8 mode on the Apple II
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;
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; Stefan Haubenthal <polluks@sdf.lonestar.org>
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; Oliver Schmidt <ol.sc@web.de>
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;
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.include "zeropage.inc"
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.include "tgi-kernel.inc"
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.include "tgi-error.inc"
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.include "apple2.inc"
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; ------------------------------------------------------------------------
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; Zero page stuff
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HBASL := $26
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HMASK := $30
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PAGE := $E6
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SCALE := $E7
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ROT := $F9
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; Graphics entry points, by cbmnut (applenut??) cbmnut@hushmail.com
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TEXT := $F399 ; Return to text screen
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HGR2 := $F3D8 ; Initialize and clear hi-res page 2.
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HGR := $F3E2 ; Initialize and clear hi-res page 1.
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HCLR := $F3F2 ; Clear the current hi-res screen to black.
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BKGND := $F3F6 ; Clear the current hi-res screen to the
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; last plotted color (from ($1C).
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HPOSN := $F411 ; Positions the hi-res cursor without
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; plotting a point.
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; Enter with (A) = Y-coordinate, and
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; (Y,X) = X-coordinate.
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HPLOT := $F457 ; Calls HPOSN and tries to plot a dot at
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; the cursor's position. If you are
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; trying to plot a non-white color at
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; a complementary color position, no
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; dot will be plotted.
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HLIN := $F53A ; Draws a line from the last plotted
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; point or line destination to:
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; (X,A) = X-coordinate, and
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; (Y) = Y-coordinate.
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HFIND := $F5CB ; Converts the hi-res coursor's position
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; back to X- and Y-coordinates; stores
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; X-coordinate at $E0,E1 and Y-coordinate
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; at $E2.
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DRAW := $F601 ; Draws a shape. Enter with (Y,X) = the
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; address of the shape table, and (A) =
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; the rotation factor. Uses the current
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; color.
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XDRAW := $F65D ; Draws a shape by inverting the existing
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; color of the dots the shape draws over.
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; Same entry parameters as DRAW.
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SETHCOL := $F6EC ; Set the hi-res color to (X), where (X)
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; must be between 0 and 7.
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; ------------------------------------------------------------------------
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; Variables mapped to the zero page segment variables. Some of these are
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; used for passing parameters to the driver.
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X1 := ptr1
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Y1 := ptr2
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X2 := ptr3
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Y2 := ptr4
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; ------------------------------------------------------------------------
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.segment "JUMPTABLE"
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; Header. Includes jump table and constants.
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; First part of the header is a structure that has a magic and defines the
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; capabilities of the driver
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.byte $74, $67, $69 ; "tgi"
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.byte TGI_API_VERSION ; TGI API version number
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.addr $0000 ; Library reference
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.word 280 ; X resolution
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.word 192 ; Y resolution
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.byte 8 ; Number of drawing colors
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pages: .byte 2 ; Number of screens available
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.byte 7 ; System font X size
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.byte 8 ; System font Y size
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.word $00EA ; Aspect ratio (based on 4/3 display)
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.byte 0 ; TGI driver flags
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; Next comes the jump table. With the exception of IRQ, all entries must be
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; valid and may point to an RTS for test versions (function not implemented).
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.addr INSTALL
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.addr UNINSTALL
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.addr INIT
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.addr DONE
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.addr GETERROR
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.addr CONTROL
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.addr CLEAR
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.addr SETVIEWPAGE
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.addr SETDRAWPAGE
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.addr SETCOLOR
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.addr SETPALETTE
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.addr GETPALETTE
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.addr GETDEFPALETTE
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.addr SETPIXEL
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.addr GETPIXEL
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.addr LINE
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.addr BAR
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.addr TEXTSTYLE
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.addr OUTTEXT
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.addr 0 ; IRQ entry is unused
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; ------------------------------------------------------------------------
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.bss
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; Absolute variables used in the code
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ERROR: .res 1 ; Error code
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; ------------------------------------------------------------------------
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.rodata
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; Constants and tables
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DEFPALETTE: .byte $00, $01, $02, $03, $04, $05, $06, $07
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FONT:
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; Beagle Bros Shape Mechanic font F.ASCII.SMALL
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; modified to exactly reproduce the text glyphs
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.incbin "a2.hi.fnt"
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; ------------------------------------------------------------------------
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.code
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; INSTALL routine. Is called after the driver is loaded into memory. May
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; initialize anything that has to be done just once. Is probably empty
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; most of the time.
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; Must set an error code: NO
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INSTALL:
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.ifdef __APPLE2ENH__
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; No page switching if 80 column store is enabled
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bit RD80COL
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bpl :+
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lda #$01
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sta pages
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: .endif
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; Fall through
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; UNINSTALL routine. Is called before the driver is removed from memory. May
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; clean up anything done by INSTALL but is probably empty most of the time.
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; Must set an error code: NO
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UNINSTALL:
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rts
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; INIT: Changes an already installed device from text mode to graphics mode.
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; Note that INIT/DONE may be called multiple times while the driver
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; is loaded, while INSTALL is only called once, so any code that is needed
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; to initializes variables and so on must go here. Setting palette and
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; clearing the screen is not needed because this is called by the graphics
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; kernel later.
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; The graphics kernel will never call INIT when a graphics mode is already
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; active, so there is no need to protect against that.
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; Must set an error code: YES
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INIT:
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; Switch into graphics mode
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bit MIXCLR
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bit HIRES
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bit TXTCLR
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; Beagle Bros Shape Mechanic fonts don't
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; scale well so use fixed scaling factor
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lda #$01
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sta SCALE
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; Done, reset the error code
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lda #TGI_ERR_OK
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sta ERROR
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rts
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; DONE: Will be called to switch the graphics device back into text mode.
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; The graphics kernel will never call DONE when no graphics mode is active,
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; so there is no need to protect against that.
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; Must set an error code: NO
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DONE:
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; Switch into text mode
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bit TXTSET
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bit LOWSCR
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.ifdef __APPLE2ENH__
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; Limit SET80COL-HISCR to text
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bit LORES
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.endif
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; Reset the text window top
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lda #$00
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sta WNDTOP
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rts
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; GETERROR: Return the error code in A and clear it.
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GETERROR:
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lda ERROR
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ldx #TGI_ERR_OK
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stx ERROR
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rts
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; CONTROL: Platform/driver specific entry point.
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; Must set an error code: YES
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CONTROL:
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; Check data msb and code to be 0
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ora ptr1+1
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bne err
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; Check data lsb to be [0..1]
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lda ptr1
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cmp #1+1
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bcs err
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; Set text window top
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tax
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beq :+
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lda #20
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: sta WNDTOP
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; Switch 4 lines of text
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.assert MIXCLR + 1 = MIXSET, error
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lda MIXCLR,x ; No BIT absolute,X available
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; Done, reset the error code
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lda #TGI_ERR_OK
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beq :+ ; Branch always
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; Done, set the error code
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err: lda #TGI_ERR_INV_ARG
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: sta ERROR
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rts
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; CLEAR: Clears the screen.
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; Must set an error code: NO
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CLEAR:
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bit $C082 ; Switch in ROM
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jsr HCLR
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bit $C080 ; Switch in LC bank 2 for R/O
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rts
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; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
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; The page number is already checked to be valid by the graphics kernel.
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; Must set an error code: NO (will only be called if page ok)
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SETVIEWPAGE:
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tax
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.assert LOWSCR + 1 = HISCR, error
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lda LOWSCR,x ; No BIT absolute,X available
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rts
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; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
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; The page number is already checked to be valid by the graphics kernel.
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; Must set an error code: NO (will only be called if page ok)
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SETDRAWPAGE:
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tax
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beq :+
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lda #>$4000 ; Page 2
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.byte $2C ; BIT absolute
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: lda #>$2000 ; Page 1
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sta PAGE
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rts
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; SETCOLOR: Set the drawing color (in A). The new color is already checked
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; to be in a valid range (0..maxcolor-1).
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; Must set an error code: NO (will only be called if color ok)
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SETCOLOR:
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bit $C082 ; Switch in ROM
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tax
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jsr SETHCOL
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bit $C080 ; Switch in LC bank 2 for R/O
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rts
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; SETPALETTE: Set the palette (not available with all drivers/hardware).
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; A pointer to the palette is passed in ptr1. Must set an error if palettes
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; are not supported
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; Must set an error code: YES
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SETPALETTE:
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lda #TGI_ERR_INV_FUNC
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sta ERROR
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rts
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; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
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; set the palette should return the default palette here, so there's no
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; way for this function to fail.
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; Must set an error code: NO
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GETPALETTE:
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; Fall through
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; GETDEFPALETTE: Return the default palette for the driver in A/X. All
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; drivers should return something reasonable here, even drivers that don't
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; support palettes, otherwise the caller has no way to determine the colors
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; of the (not changeable) palette.
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; Must set an error code: NO (all drivers must have a default palette)
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GETDEFPALETTE:
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lda #<DEFPALETTE
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ldx #>DEFPALETTE
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rts
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; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
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; color. The coordinates passed to this function are never outside the
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; visible screen area, so there is no need for clipping inside this function.
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; Must set an error code: NO
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SETPIXEL:
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bit $C082 ; Switch in ROM
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ldx X1
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ldy X1+1
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lda Y1
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jsr HPLOT
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bit $C080 ; Switch in LC bank 2 for R/O
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rts
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; GETPIXEL: Read the color value of a pixel and return it in A/X. The
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; coordinates passed to this function are never outside the visible screen
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; area, so there is no need for clipping inside this function.
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GETPIXEL:
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bit $C082 ; Switch in ROM
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ldx X1
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ldy X1+1
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lda Y1
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jsr HPOSN
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lda (HBASL),y
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and HMASK
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asl
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beq :+ ; 0 (black)
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lda #$03 ; 3 (white)
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: bcc :+
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adc #$03 ; += 4 (black -> black2, white -> white2)
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: ldx #$00
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bit $C080 ; Switch in LC bank 2 for R/O
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rts
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; LINE: Draw a line from X1/Y1 to X2/Y2, where X1/Y1 = ptr1/ptr2 and
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; X2/Y2 = ptr3/ptr4 using the current drawing color.
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; Must set an error code: NO
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LINE:
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bit $C082 ; Switch in ROM
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ldx X1
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ldy X1+1
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lda Y1
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jsr HPOSN
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lda X2
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ldx X2+1
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ldy Y2
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jsr HLIN
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bit $C080 ; Switch in LC bank 2 for R/O
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rts
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; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
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; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
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; Contrary to most other functions, the graphics kernel will sort and clip
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; the coordinates before calling the driver, so on entry the following
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; conditions are valid:
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; X1 <= X2
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; Y1 <= Y2
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; (X1 >= 0) && (X1 < XRES)
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; (X2 >= 0) && (X2 < XRES)
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; (Y1 >= 0) && (Y1 < YRES)
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; (Y2 >= 0) && (Y2 < YRES)
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; Must set an error code: NO
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BAR:
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inc Y2
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: lda Y2
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pha
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lda Y1
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sta Y2
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jsr LINE
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pla
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sta Y2
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inc Y1
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cmp Y1
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bne :-
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rts
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; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
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; direction is passend in X/Y, the text direction is passed in A.
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; Must set an error code: NO
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TEXTSTYLE:
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cmp #TGI_TEXT_VERTICAL
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bne :+
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lda #48
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: sta ROT
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rts
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; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
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; current text style. The text to output is given as a zero terminated
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; string with address in ptr3.
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; Must set an error code: NO
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OUTTEXT:
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bit $C082 ; Switch in ROM
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lda X1
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ldy X1+1
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ldx ROT
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php ; Save Z flag
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beq :+ ; Not horizontal
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sec
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sbc #$07 ; Adjust X
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bcs :+
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dey
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: tax
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lda Y1
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plp ; Restore Z flag
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bne :+ ; Not vertical
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sec
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sbc #$07 ; Adjust Y
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: jsr HPOSN
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clc
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lda FONT+2*99 ; "connection char"
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adc #<FONT
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sta ptr4
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lda FONT+2*99+1 ; "connection char"
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adc #>FONT
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sta ptr4+1
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ldy #$00
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: lda (ptr3),y
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beq :+
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sty tmp1 ; Save string index
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sec
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sbc #$1F ; No control chars
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asl ; Offset * 2
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tay
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clc
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lda FONT,y
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adc #<FONT
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tax
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lda FONT+1,y
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adc #>FONT
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tay
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lda ROT
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jsr DRAW ; Draw char from string
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ldx ptr4
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ldy ptr4+1
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lda ROT
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jsr DRAW ; Draw "connection char"
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ldy tmp1 ; Restore string index
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iny
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bne :- ; Branch always
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: bit $C080 ; Switch in LC bank 2 for R/O
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rts
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