emailler/drivers/a2input.s

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.export get_key
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.export check_for_abort_key
.export get_key_if_available
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.export get_key_ip65
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.import ip65_process
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.code
; use Apple 2 monitor ROM function to read from keyboard
; inputs: none
; outputs: A contains ASCII code of key pressed
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get_key = $fd0c
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; inputs: none
; outputs: A contains ASCII value of key just pressed (0 if no key pressed)
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get_key_if_available:
lda $c000 ; current key pressed
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bmi got_key
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lda #0
rts
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; process inbound ip packets while waiting for a keypress
get_key_ip65:
jsr ip65_process
lda $c000 ; key down?
bpl get_key_ip65
got_key:
bit $c010 ; clear the keyboard strobe
and #$7f
rts
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; check whether the escape key is being pressed
; inputs: none
; outputs: sec if escape pressed, clear otherwise
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check_for_abort_key:
lda $c000 ; current key pressed
cmp #$9b
bne :+
bit $c010 ; clear the keyboard strobe
sec
rts
: clc
rts
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; -- LICENSE FOR a2input.s --
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; The contents of this file are subject to the Mozilla Public License
; Version 1.1 (the "License"); you may not use this file except in
; compliance with the License. You may obtain a copy of the License at
; http://www.mozilla.org/MPL/
;
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; Software distributed under the License is distributed on an "AS IS"
; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
; License for the specific language governing rights and limitations
; under the License.
;
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; The Original Code is ip65.
;
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; The Initial Developer of the Original Code is Jonno Downes,
; jonno@jamtronix.com.
; Portions created by the Initial Developer are Copyright (C) 2009
; Jonno Downes. All Rights Reserved.
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; -- LICENSE END --