mirror of https://github.com/cc65/cc65.git
40 lines
1.1 KiB
ArmAsm
40 lines
1.1 KiB
ArmAsm
;
|
|
; Mariano Domínguez
|
|
; 2022-12-4
|
|
;
|
|
; atari lib
|
|
;
|
|
.include "atari.inc"
|
|
.export __sound
|
|
.import popa
|
|
; play sound, arguments: voice, pitch, distortion, volume. same as BASIC
|
|
.proc __sound
|
|
sta STORE2 ;save volume
|
|
jsr popa ;get distortion
|
|
sta STORE1 ;save distortion
|
|
jsr popa ;get pitch
|
|
pha ;save in stack
|
|
jsr popa ;get voice
|
|
asl a ;adjust voice *2 for offset in x
|
|
tax
|
|
pla ;get pitch from stack
|
|
sta AUDF1,x ;store pitch
|
|
lda #0
|
|
sta AUDCTL
|
|
lda #3
|
|
stx SKCTL ;init sound
|
|
lda STORE1 ;get distortion
|
|
asl a ;ignore the high nibble
|
|
asl a
|
|
asl a
|
|
asl a
|
|
clc ;setup for adding volume
|
|
adc STORE2 ;add volume
|
|
sta AUDC1,x ;volume + distortion in control channel
|
|
rts
|
|
.endproc
|
|
;reserve 2 bytes for temp storage
|
|
.bss
|
|
STORE1: .res 1
|
|
STORE2: .res 1
|