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42 lines
958 B
ArmAsm
42 lines
958 B
ArmAsm
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; Karri Kaksonen, 2004-11-01
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;
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; char cgetc (void);
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;
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.export _cgetc
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.import _kbhit
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.import KBBUF
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; --------------------------------------------------------------------------
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; The Atari Lynx has a very small keyboard - only 3 keys
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; Opt1, Opt2 and Pause.
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; But the designers have decided that pressing Pause and Opt1 at the
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; same time means Restart and pressing Pause and Opt2 means Flip screen.
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; For "easter egg" use I have also included all three keys pressed '?'
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; and Opt1 + Opt2 pressed '3'.
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; So the keyboard returns '1', '2', '3', 'P', 'R', 'F' or '?'.
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_cgetc:
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jsr _kbhit ; Check for char available
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tax ; Test result
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beq _cgetc
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ldx #5 ; Wait for some time... 0.2 seconds or so.
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@L1: ldy #255
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@L2: lda #255
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@L3: dec
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bne @L3
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dey
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bne @L2
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dex
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bne @L1
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jsr _kbhit ; Check for double pressed buttons
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lda KBBUF
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stz KBBUF
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ldx #0
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rts
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