emailler/docs/drivers_vic20print_s.html

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<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/><link rel="stylesheet" type="text/css" href="ca65-doc-style.css"/></head><body><a href="ref_index.html"><h1>ip65 technical reference</h1></a><h1>File : drivers/vic20print.s</h1><h2 id="functions">functions</h2><table><tr><th>function</th><th>description</th></tr><tr><td id="beep">beep</td><td><pre>currently does nothing (should make a 'beep noise')
inputs: none
outputs: none
</pre></td></tr><tr><td id="cls">cls</td><td><pre>use VIC 20 Kernel ROM function to clear the screen
inputs: none
outputs: none
</pre></td></tr><tr><td id="print_a">print_a</td><td><pre>use VIC 20 Kernel ROM function to print a character to the screen
inputs: A contains petscii value of character to print
outputs: none
</pre></td></tr><tr><td id="print_a_inverse">print_a_inverse</td><td><pre>print a single char in inverse text:
</pre></td></tr><tr><td id="print_cr">print_cr</td><td><pre>use VIC 20 Kernel ROM function to move to a new line
inputs: none
outputs: none
</pre></td></tr></table><h2 id="constants">constants</h2><table><tr><th>constants</th><th>description</th><th>value</th></tr><tr><td id="screen_current_col">screen_current_col</td><td></td><td>$d3
</td></tr><tr><td id="screen_current_row">screen_current_row</td><td></td><td>$d6
</td></tr></table><h2>implementation</h2><pre id="code">
.export print_a
.export print_cr
.export cls
.export beep
.export print_a_inverse
.import timer_read
.exportzp screen_current_row
.exportzp screen_current_col
screen_current_row=$d6
screen_current_col=$d3
;use VIC 20 Kernel ROM function to print a character to the screen
;inputs: A contains petscii value of character to print
;outputs: none
print_a = $ffd2
.bss
beep_timer: .res 1
.code
;use VIC 20 Kernel ROM function to move to a new line
;inputs: none
;outputs: none
print_cr:
lda #13
jmp print_a
;use VIC 20 Kernel ROM function to clear the screen
;inputs: none
;outputs: none
cls:
lda #147 ; 'CLR/HOME'
jmp print_a
;currently does nothing (should make a 'beep noise')
;inputs: none
;outputs: none
beep:
lda $900e
ora #15
sta $900e ;set volume
;turn on osc. 3
lda #$FF
sta $900c
; pause for qtr second
jsr timer_read
stx beep_timer
inc beep_timer
inc beep_timer
:
jsr timer_read
cpx beep_timer
bne :-
;turn off osc. 3
lda #$00
sta $900c
rts
;print a single char in inverse text:
print_a_inverse:
pha
lda #18 ;inverse mode on
jsr print_a
pla
jsr print_a
lda #146 ;inverse mode off
jmp print_a
; 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/
;
; 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.
;
; The Original Code is ip65.
;
; 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.
; -- LICENSE END --
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