95 lines
1.9 KiB
ArmAsm
95 lines
1.9 KiB
ArmAsm
.export print_a
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.export print_cr
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.export cls
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.export beep
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.export print_a_inverse
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.import timer_read
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.exportzp screen_current_row
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.exportzp screen_current_col
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screen_current_row = $d6
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screen_current_col = $d3
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; use VIC 20 Kernel ROM function to print a character to the screen
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; inputs: A contains petscii value of character to print
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; 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
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; use VIC 20 Kernel ROM function to move to a new line
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; inputs: none
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; outputs: none
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print_cr:
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lda #13
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jmp print_a
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; use VIC 20 Kernel ROM function to clear the screen
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; inputs: none
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; outputs: none
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cls:
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lda #147 ; 'CLR/HOME'
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jmp print_a
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; currently does nothing (should make a 'beep noise')
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; inputs: none
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; outputs: none
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beep:
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lda $900e
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ora #15
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sta $900e ; set volume
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; turn on osc. 3
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lda #$FF
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sta $900c
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; pause for qtr second
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jsr timer_read
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stx beep_timer
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inc beep_timer
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inc beep_timer
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: jsr timer_read
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cpx beep_timer
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bne :-
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; turn off osc. 3
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lda #$00
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sta $900c
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rts
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; print a single char in inverse text:
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print_a_inverse:
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pha
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lda #18 ; inverse mode on
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jsr print_a
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pla
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jsr print_a
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lda #146 ; inverse mode off
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jmp print_a
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; The contents of this file are subject to the Mozilla Public License
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; Version 1.1 (the "License"); you may not use this file except in
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; compliance with the License. You may obtain a copy of the License at
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; http://www.mozilla.org/MPL/
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;
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; Software distributed under the License is distributed on an "AS IS"
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; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
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; License for the specific language governing rights and limitations
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; under the License.
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;
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; The Original Code is ip65.
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;
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; The Initial Developer of the Original Code is Jonno Downes,
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; jonno@jamtronix.com.
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; Portions created by the Initial Developer are Copyright (C) 2009
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; Jonno Downes. All Rights Reserved.
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; -- LICENSE END --
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