2018-09-17 00:30:25 +00:00
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;Screen Control Assembly Lanuage Routines for Apple 1
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2019-11-20 06:06:34 +00:00
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SUBROUTINE _SCREEN
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SMTEXT EQU $00 ;Default Text Screen
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SMWIDE EQU $FF ;Wide Text Screen (Undefined)
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;Set Screen Mode
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2020-04-27 16:32:18 +00:00
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SETSCR: CMP #SMTEXT ;If Default Text Screen
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2019-11-20 06:06:34 +00:00
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BEQ GETSCR ;Return Return 0
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LDA #$FF ;Else Return ERROR
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RTS
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;Else Return 0
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;Get Screen Mode
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GETSCR: LDA #0 ;Return 0 (Default Text Mode)
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RTS
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2018-09-17 00:30:25 +00:00
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;Clear the Screen
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CLRSCR: RTS ;Do Nothing (Drop to RTS)
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2019-11-20 06:06:34 +00:00
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;Move Cursor Home
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CRSRHM EQU CLRSCR ;No Action
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2018-09-17 00:30:25 +00:00
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;Move Cursor to Specified Coordinates
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SETPOS EQU CLRSCR ;No Action
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;Get Cursor Position
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GETPOS: LDA #$FF ;Return Error
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TAY
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RTS
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;Get Screen Size
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GETSIZ: LDA #40 ;40 Columns
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LDY #24 ;24 Lines
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RTS
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