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24 lines
493 B
ArmAsm
24 lines
493 B
ArmAsm
;
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; Kevin Ruland
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; char cgetc (void);
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;
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; If open_apple key is pressed then the high-bit of the key is set.
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;
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.export _cgetc
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.include "apple2.inc"
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_cgetc:
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lda KBD
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bpl _cgetc ; if < 128, no key pressed
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; At this time, the high bit of the key pressed is set
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bit KBDSTRB ; clear keyboard strobe
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bit BUTN0 ; check if OpenApple is down
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bmi :+
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and #$7F ; If not down, then clear high bit
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: ldx #$00
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rts
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