emailler/drivers/c64print.s

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.export print_a
.export print_cr
.export cls
.export beep
.export print_a_inverse
.exportzp screen_current_row
.exportzp screen_current_col
screen_current_row = $d6
screen_current_col = $d3
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; use C64 Kernel ROM function to print a character to the screen
; inputs: A contains petscii value of character to print
; outputs: none
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print_a = $ffd2
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.bss
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beep_timer: .res 1
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.code
; use C64 Kernel ROM function to move to a new line
; inputs: none
; outputs: none
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print_cr:
lda #13
jmp print_a
; use C64 Kernel ROM function to clear the screen
; inputs: none
; outputs: none
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cls:
lda #147 ; 'CLR/HOME'
jmp print_a
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; currently does nothing (should make a 'beep noise')
; inputs: none
; outputs: none
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beep:
lda #15
sta $d418 ; set volume
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lda #0
sta $d405
lda #240
sta $d406
lda #8
sta $d403
; tone values for voice 1
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lda #48
sta $d400
lda #28
sta $d401
; enable tone register
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lda #65
sta $d404
; pause for qtr second
lda $dd06
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sta beep_timer
inc beep_timer ; time counts backwards
: lda $dd06
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cmp beep_timer
bne :-
; disable tone register
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lda #65
sta $d404
lda #0
sta $d418 ; set volume
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rts
; print a single char in inverse text:
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print_a_inverse:
pha
lda #18 ; inverse mode on
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jsr print_a
pla
jsr print_a
lda #146 ; inverse mode off
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jmp print_a
; -- LICENSE FOR c64print.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 --