3edb959298
In order to avoid undefined behaviour of programs not aware of 80 column mode, the 80 column firmware deliberately doesn't use CH but OURCH. So in order to be fully interoperable, CONIO needs to do the same. This changes introduces that behavior. So far so good. But the 80 column firmware can also be active in 40 column mode. This scenario is not detectable with reasonable effort. Therefore the behaviour of CONIO in this scenario is _not_ improved. However, this scenario is supposed to be very uncommon - and a recent update to videomode() makes sure to not activate it anymore ourselves. Notes: * If a program wants to be 100% sure to not run in 40 column mode with 80 column firmware active it can call videomode(VIDEOMODE_40COL) to explicitly deactivate a potentially active 80 column firmware. However, this always implicitly clears the screen. * In 40 column mode (contrast to 80 column mode) the 80 column firmware updates CH to reflect OURCH. So as long as CONIO only reads CH, but doesn't update it, everything works as expected. Interestingly this makes a rather useful scenario of STDIO/CONIO interoperation work: Using STDIO for screen output and CONIO for keyboard input. When cgetc() is called after cursor(1), it has to write to the screen as there's no hardware cursor on the Apple II. Those writes work as expected even in 40 column mode with active 80 column firmware as CH is only read but not written.
94 lines
3.4 KiB
PHP
94 lines
3.4 KiB
PHP
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;-----------------------------------------------------------------------------
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; Zero page
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WNDLFT := $20 ; Text window left
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WNDWDTH := $21 ; Text window width
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WNDTOP := $22 ; Text window top
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WNDBTM := $23 ; Text window bottom+1
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CH := $24 ; Cursor horizontal position
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CV := $25 ; Cursor vertical position
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BASL := $28 ; Text base address low
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BASH := $29 ; Text base address high
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INVFLG := $32 ; Normal/inverse(/flash)
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PROMPT := $33 ; Used by GETLN
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RNDL := $4E ; Random counter low
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RNDH := $4F ; Random counter high
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HIMEM := $73 ; Highest available memory address+1
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CURLIN := $75 ; Current line number being executed
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;-----------------------------------------------------------------------------
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; Vectors
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DOSWARM := $03D0 ; DOS warmstart vector
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BRKVec := $03F0 ; Break vector
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SOFTEV := $03F2 ; Vector for warm start
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PWREDUP := $03F4 ; This must be = EOR #$A5 of SOFTEV+1
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;-----------------------------------------------------------------------------
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; 80 column firmware
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OURCH := $057B ; Cursor horizontal position
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OURCV := $05FB ; Cursor vertical position
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;-----------------------------------------------------------------------------
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; Hardware
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; Keyboard input
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KBD := $C000 ; Read keyboard
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KBDSTRB := $C010 ; Clear keyboard strobe
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; 80 column video
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CLR80COL:= $C000 ; Disable 80 column store
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SET80COL:= $C001 ; Enable 80 column store
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RD80COL := $C018 ; >127 if 80 column store enabled
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RD80VID := $C01F ; >127 if 80 column video enabled
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; Character set
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CLRALTCHAR := $C00E ; Normal Apple II char set
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SETALTCHAR := $C00F ; Norm/inv LC, no flash
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ALTCHARSET := $C01E ; >127 if alt charset switched in
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; Language card
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RDLCBNK2:= $C011 ; >127 if LC bank 2 in use
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RDLCRAM := $C012 ; >127 if LC is read enabled
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ROMIN := $C081 ; Swap in D000-FFFF ROM
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LCBANK2 := $C083 ; Swap in LC bank 2
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LCBANK1 := $C08B ; Swap in LC bank 1
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; Vertical blanking
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RDVBLBAR := $C019 ; >127 if not vertical blanking
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RDVBLMSK := $C041 ; >127 if VBL interrupts enabled
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DISVBL := $C05A ; Disable VBL interrupts
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ENVBL := $C05B ; Enable VBL interrupts
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; Video mode
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TXTCLR := $C050 ; Display graphics
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TXTSET := $C051 ; Display text
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MIXCLR := $C052 ; Disable 4 lines of text
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MIXSET := $C053 ; Enable 4 lines of text
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LOWSCR := $C054 ; Page 1
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HISCR := $C055 ; Page 2
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LORES := $C056 ; Lores graphics
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HIRES := $C057 ; Hires graphics
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DHIRESON := $C05E ; Enable double-width graphics
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DHIRESOFF := $C05F ; Disable double-width graphics
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; Game controller
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TAPEIN := $C060 ; Read casette input / Switch input 3
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BUTN0 := $C061 ; Switch input 0 / Open-Apple key
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BUTN1 := $C062 ; Switch input 1 / Closed-Apple key
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BUTN2 := $C063 ; Switch input 2 / Shift key
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PADDL0 := $C064 ; Analog input 0
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PADDL1 := $C065 ; Analog input 1
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PADDL2 := $C066 ; Analog input 2
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PADDL3 := $C067 ; Analog input 3
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PTRIG := $C070 ; Analog input reset
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; Input/Output Unit
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IOUDISON := $C07E ; Disable IOU
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IOUDISOFF := $C07F ; Enable IOU
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; Control Your Apple
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CYAREG := $C036 ; Bits 0-3=disk detect 4=shadow all banks 7=fast
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