emailler/drivers/c64print.s

109 lines
2.1 KiB
ArmAsm

.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
; use C64 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 C64 Kernel ROM function to move to a new line
; inputs: none
; outputs: none
print_cr:
lda #13
jmp print_a
; use C64 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 #15
sta $d418 ; set volume
lda #0
sta $d405
lda #240
sta $d406
lda #8
sta $d403
; tone values for voice 1
lda #48
sta $d400
lda #28
sta $d401
; enable tone register
lda #65
sta $d404
; pause for qtr second
lda $dd06
sta beep_timer
inc beep_timer ; time counts backwards
: lda $dd06
cmp beep_timer
bne :-
; disable tone register
lda #65
sta $d404
lda #0
sta $d418 ; set volume
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
; -- LICENSE FOR c64print.s --
; 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 --