I am working on an assembly program (8086) that plays music on the PC speaker.
Everything works fine but I've got one problem. Program falls in endless sleep (with speaker on) on 78th note, no matter what note it is.
I am using 86h function of 15 interrupt.
So why does that endless sleep occur, and how to fix that?
Here's the code (with Mortal Kombat Theme):
;constants
TB equ 38636; 1.19MHz/30Hz
TC equ 34546; 1.19MHz/33Hz
TD equ 30811; 1.19MHz/37Hz
TE equ 27805; 1.19MHz/41Hz
TF equ 25909; 1.19MHz/44Hz
TG equ 23265; 1.19MHz/49Hz
TA equ 20727; 1.19MHz/55Hz
TH equ 18387; 1.19MHz/62Hz
TP equ 1;pause
;K end of melody
strophe1n equ 'ACADAEDCCECGCECGGHGCGDCFFAFCFCH'
strophe1o equ '3434344444444443333434433334343'
strophe1t equ '2222222222222222222222222222222'
strophe2n equ 'APAPAPAPGCAPAPAPAPGEAPAPAPAPGCAPAPAPAPAPAPA'
strophe2o equ '4040404045404040404440404040454040404040404'
strophe2t equ '2424242422242424242224242424222424284844484'
strophe3n equ 'AEACABACABGAEACABACABGAEACABACABGAEACGPGGPGAAPAA'
strophe3o equ '454545454544545454545445454545454454540440444044'
strophe3t equ '424242424424242424244242424242442424248488448848'
Progr segment
assume cs:Progr, ds:data, ss:stacky
interval:; waits DX:CX microseconds
mov ah,86h;
int 15h
ret
;here come notes every note set up its time and sleep
note:;0,5 sec
mov cx,7;
mov dx,41248;
call interval
ret
halfnote:;0,25sec
mov cx,3;
mov dx,53280;
call interval
ret
quarternote:;0,125sec
mov cx,1;
mov dx,58982;
call interval
ret
eighthnote:
mov cx,0;
mov dx,62455;
call interval
ret
turnon:;sets tone and turn on speaker
;setting up tone
mov ax,tone
mov dx,42h
out dx,al
mov al,ah
out dx,al
;turning speaker on
mov dx,61h
in al,dx;
or al,00000011B;
out dx,al;
ret
turnoff:;turning speaker off
mov dx,61h
in al,dx;
and al,11111100B;
out dx,al;
ret
play:
;simple switch for times
call turnon
cmp time,1
je whole
cmp time,2
je half
cmp time,4
je quarter
cmp time,8
je eighth
whole: call note;sleep for note time (while speaker is on) and then shuts up the speaker
jmp endplay
half: call halfnote
jmp endplay
quarter: call quarternote
jmp endplay
eighth: call eighthnote
jmp endplay
endplay:
call turnoff; turning speaker off
ret
exit:
mov ah,4ch
mov al,00h
int 21h;
;START--------------------------------------------------------------------
start: mov ax,data ;some start up
mov ds,ax
mov ax,stacky
mov ss,ax
mov sp,offset peak
mov si,0
melody:
lea bx,notes
mov dl,ds:[bx+si];dl = next note
cmp dl,'K'; if K then melody ends
je exit
;simple switch for notes
cmp dl,'A'
je A
cmp dl,'B'
je B
cmp dl,'C'
je C
cmp dl,'D'
je D
cmp dl,'E'
je E
cmp dl,'F'
je F
cmp dl,'G'
je G
cmp dl,'H'
je H
mov tone,TP
readoctave:
lea bx,octaves;reads next octave from array
mov cl,ds:[bx+si]
sub cl,'0'
shr tone,cl; double the tone octave times (tone = tone *2^octave)
lea bx,times;read next time from array
mov cl,ds:[bx+si]
sub cl,'0'
mov time,cl
call play;
inc si;;next index
jmp melody;play next note
;notes asignment
A: mov tone,TA
jmp readoctave
B: mov tone,TB
jmp readoctave
C: mov tone,TC
jmp readoctave
D: mov tone,TD
jmp readoctave
E: mov tone,TE
jmp readoctave
F: mov tone,TF
jmp readoctave
G: mov tone,TG
jmp readoctave
H: mov tone,TH
jmp readoctave
Progr ends
data segment
notes db strophe1n,strophe2n,strophe3n,'K';notes k means end of melody
octaves db strophe1o,strophe2o,strophe3o,'0';octaves, tone =(tone = frequency of note *2^octave)
times db strophe1t,strophe2t,strophe3t,'0';just times to play each note
tone dw 0
time db 0
data ends
stacky segment
dw 100h dup(0)
peak Label word
stacky ends
end start
I know that the code is kind of big but I don't know where's the issue.
@EDIT Maybe array size is too big but i dont think so @EDIT2 Program fails on 78th note, no matter what note it is.
It turned out that the
interval:
mov ah,86h;
int 15h
ret
works wrong beacause int 15h 86h function somehow fails,
so I wrote my own procedure
interval:
mov ah, 0
int 1Ah ; actual time
mov bx,dx
delay:
mov ah, 0
int 1Ah
sub dx,bx
cmp di,dx
ja delay
ret
also notes define their time in other way(now in di register)e.g.:
note:;0,5 sec
mov di, 8
call interval
ret
halfnote:;0,25 sec
mov di, 4
call interval
ret