243 lines
22 KiB
Plaintext
243 lines
22 KiB
Plaintext
''********************************************
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''* VGA 512x384 2-Color Bitmap Driver v1.0 *
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''* (C) 2006 Parallax, Inc. *
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''********************************************
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''
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'' This object generates a 512x384 pixel bitmap, signaled as 1024x768 VGA.
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'' Each pixel is one bit, so the entire bitmap requires 512 x 384 / 32 longs,
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'' or 6,144 longs (24KB). Color words comprised of two byte fields provide
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'' unique colors for every 32x32 pixel group. These color words require 512/32
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'' * 384/32 words, or 192 words. Pixel memory and color memory are arranged
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'' left-to-right then top-to-bottom.
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''
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'' A sync indicator signals each time the screen is drawn (you may ignore).
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''
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'' You must provide buffers for the colors, pixels, and sync. Once started,
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'' all interfacing is done via memory. To this object, all buffers are read-
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'' only, with the exception of the sync indicator which gets written with a
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'' non-0 value. You may freely write all buffers to affect screen appearance.
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''
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{{
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notizen:
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}}
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CON
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' 512x384 settings - signals as 1024 x 768 @ 67Hz
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hp = 512 'horizontal pixels
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vp = 384 'vertical pixels
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hf = 8 'horizontal front porch pixels
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hs = 48 'horizontal sync pixels
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hb = 88 'horizontal back porch pixels
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vf = 1 'vertical front porch lines
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vs = 3 'vertical sync lines
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vb = 28 'vertical back porch lines
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' ?nderung wegen synchronisationsproblemen bei board r13
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' hn = 1 'horizontal normal sync state (0|1)
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' vn = 1 'vertical normal sync state (0|1)
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hn = 0 'horizontal normal sync state (0|1)
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vn = 0 'vertical normal sync state (0|1)
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pr = 35 'pixel rate in MHz at 80MHz system clock (5MHz granularity)
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' Tiles
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xtiles = hp / 32 'xtiles 16
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ytiles = vp / 32 'ytiles 12
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' H/V inactive states
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hv_inactive = (hn << 1 + vn) * $0101
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VAR long cog
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PUB start(BasePin, ColorPtr, PixelPtr, SyncPtr) : okay | i, j
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'' Start VGA driver - starts a COG
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'' returns false if no COG available
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''
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'' BasePin = VGA starting pin (0, 8, 16, 24, etc.)
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''
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'' ColorPtr = Pointer to 192 words which define the "0" and "1" colors for
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'' each 32x32 pixel group. The lower byte of each word contains
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'' the "0" bit RGB data while the upper byte of each word contains
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'' the "1" bit RGB data for the associated group. The RGB
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'' data in each byte is arranged as %RRGGBB00 (4 levels each).
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''
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'' color word example: %%0020_3300 = "0" = gold, "1" = blue
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''
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'' PixelPtr = Pointer to 6,144 longs containing pixels that make up the 512 x
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'' 384 pixel bitmap. Longs' LSBs appear left on the screen, while
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'' MSBs appear right. The longs are arranged in sequence from left-
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'' to-right, then top-to-bottom.
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''
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'' SyncPtr = Pointer to long which gets written with non-0 upon each screen
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'' refresh. May be used to time writes/scrolls, so that chopiness
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'' can be avoided. You must clear it each time if you want to see
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'' it re-trigger.
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'if driver is already running, stop it
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stop
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'implant pin settings and pointers, then launch COG
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' %1111_1111_1111_1111_1111_1111_1111_1111
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' 2 0 0 0 0 0 F F
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' 0010_0000_0000_0000_0000_0000_1111_1111
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' || ||| VGroup
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' || |||| |||| VPins Video an allen 8 Pins - VGA
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' || --> 01 VMode VGA-Mode
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' | --> 0 CMode 2-Farbmodus
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reg_vcfg := $200000FF + (BasePin & %111000) << 6 'schreibt VGroup in das Konfigurationsregister
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i := $FF << (BasePin & %011000) 'acht Bits in der Maske bis zur BasePin-Position verschieben
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j := BasePin & %100000 == 0
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reg_dira := i & j
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reg_dirb := i & !j
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' clrflag := 1 '1 - bildschirm wird bei jedem durchlauf gel?scht
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' clrline := 2 'tilezeile ab der gel?scht wird
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longmove(@color_base, @ColorPtr, 2) 'kopiert 2 parameter von color_ptr in den asm-bereich color_base
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'color_ptr --> color_base
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'pixel_pointer --> pixel_base
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if (cog := cognew(@init, SyncPtr) + 1)
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return true
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PUB stop | i
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'' Stop VGA driver - frees a COG
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if cog
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cogstop(cog~ - 1)
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DAT
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'***********************************************
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'* Assembly language VGA 2-color bitmap driver *
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'***********************************************
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org 'set origin to $000 for start of program
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' Initialization code - init I/O
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init mov dira,reg_dira 'i/o-register konfigurieren
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mov dirb,reg_dirb
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movi ctra,#%00001_101 'enable PLL in ctra (VCO runs at 4x)
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'25..23 PLLDIV = 101 --> VCO / 4
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'31..26 CTRMODE = 00001 --> PLL intern (Video Mode)
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movi frqa,#(pr / 5) << 3 'set pixel rate
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' (35 MHz / 5) << 3 = 56 = 111000
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mov vcfg,reg_vcfg 'set video configuration
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' Main loop, display field and do invisible sync lines
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field mov color_ptr,color_base 'reset color pointer 'color-pointer auf anfangswert setzen
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mov pixel_ptr,pixel_base 'reset pixel pointer 'pixel-pointer auf anfangswert setzen
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mov y,#ytiles 'set y tiles
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:ytile mov yl,#32 'set y lines per tile
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:yline mov yx,#2 'set y expansion
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:yexpand mov x,#xtiles 'set x tiles
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mov vscl,vscl_pixel 'set pixel vscl
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:xtile rdword color,color_ptr 'get color word 'color <-- (color_ptr)
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and color,colormask 'clear h/v bits
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or color,hv 'set h/v inactive states
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rdlong pixel,pixel_ptr 'get pixel long 'pixel <-- (pixel_ptr)
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'-----------------------------------------------------
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wrlong reg_a,pixel_ptr 'screen sofort bei darstellung löschen
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'-----------------------------------------------------
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waitvid color,pixel 'farb- und pixelwerte (32bit) ausgeben
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add color_ptr,#2 'point to next color word 'farbe nur zwei byte, also ein word
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add pixel_ptr,#4 'point to next pixel long 'pixel vier byte, also ein long
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djnz x,#:xtile 'another x tile? 'schleife x * 32bit-pixelwerte
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sub color_ptr,#xtiles * 2 'farbzeiger auf zeilenanfang r?cksetzen
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sub pixel_ptr,#xtiles * 4 'pixelzeiger auf zeilenanfang r?cksetzen
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mov x,#1 'zeilensynchronimpuls
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call #hsync
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'----------------------------------------------------- VIDEOZEILEN
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djnz yx,#:yexpand 'y expand?
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'----------------------------------------------------- PIXELZEILEN
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add pixel_ptr,#xtiles * 4 'pixelzeiger auf n?chsten zeilenanfang setzen
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djnz yl,#:yline 'another y line in same tile? 'schleife y-tilezeilen
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'----------------------------------------------------- TILEZEILEN
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add color_ptr,#xtiles * 2 'farbzeiger auf n?chsten zeilenanfang setzen
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djnz y,#:ytile 'another y tile?
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'----------------------------------------------------- BILDSCHIRM
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wrlong colormask,par 'ende sichtbarer bereich, sync f?r software erzeugen
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mov x,#vf 'leerzeilen (vf - vertical front)
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call #blank
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mov x,#vs 'bildsynchonisation (x zeilen)
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call #vsync
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mov x,#vb 'do vertical back porch lines
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call #vsync
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jmp #field 'field done, loop
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' Subroutine - do blank lines
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vsync xor hvsync,#$101 'flip vertical sync bits
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blank mov vscl,hvis 'do blank pixels
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waitvid hvsync,#0
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hsync mov vscl,#hf 'do horizontal front porch pixels
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waitvid hvsync,#0
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mov vscl,#hs 'do horizontal sync pixels
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waitvid hvsync,#1
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mov vscl,#hb 'do horizontal back porch pixels
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waitvid hvsync,#0
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djnz x,#blank 'another line?
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hsync_ret
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blank_ret
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vsync_ret ret
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' Data
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reg_dira long 0 'set at runtime
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reg_dirb long 0 'set at runtime
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reg_vcfg long 0 'set at runtime
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color_base long 0 'set at runtime (2 contiguous longs)
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pixel_base long 0 'set at runtime
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vscl_pixel long 1 << 12 + 32 '1 pixel per clock and 32 pixels per set
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colormask long $FCFC 'mask to isolate R,G,B bits from H,V
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hvis long hp 'visible pixels per scan line
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hv long hv_inactive '-H,-V states
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hvsync long hv_inactive ^ $200 '+/-H,-V states
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reg_a long 0 'temp. register
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' Uninitialized data
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color_ptr res 1
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pixel_ptr res 1
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color res 1
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pixel res 1
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x res 1
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y res 1
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yl res 1
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yx res 1
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