M EQU 59

D4 = (10500000000/88/117466+M/2)/M
C4 = (10500000000/88/104650+M/2)/M
H3 = (10500000000/88/93388+M/2)/M;93233+M/2)/M
A3 = (10500000000/88/88000+M/2)/M
G3 = (10500000000/88/78399+M/2)/M
F3 = (10500000000/88/69846+M/2)/M
E3 = (10500000000/88/65568+M/2)/M;65925+M/2)/M
C3 = (10500000000/88/52325+M/2)/M

ORG 256
;---------------------------------------------------------------------
 MOV AL,0B6H		; not necesary
 OUT 43H,AL		; just make it more compatible
main:
 HLT
 INC BX 		; BX=timer counter
 MOV AL,BL		; get timer counter
 MOV SI,table
 CMP AL,208+12
 JC @F
 MOV SI,table+18;36
@@:
 AND AX,127		; put zero in AH
 SUB AL,12
 JC mute
 XCHG BP,AX		; get channel1 data
 SHR BP,1
 MOV AL,[BP+SI]
 JNC @F
 SHR AL,4
@@:
 AND AL,15
 JZ mute
 ADD AL,16
 CMP AL,18
 JNE @F
 MOV AL,C3
@@:
 MOV AH,M		; counter = data * Multiplier
mute:
 MUL AH
beep:
 OUT 42H,AL		; lowbyte of the counter
 MOV AL,AH
 OUT 42H,AL		; highbyte of the counter
 SALC			; if pause then speaker turn off
 OUT 61H,AL		; else turn on
;---------------------------------------------------------------------
 CBW			; if speaker off then AH=0
 IN AL,60H		; if ESC pressed then AL=1
 DEC AX 		; if AX=1 then EXIT
 JNZ main
RETN			; exit to DOS
;---------------------------------------------------------------------
table:			; notes data, 0 -> pause

DD 0x00000313;DB  03,01,03,00,	00,00,00,00
DD 0x00000777;DB  07,07,07,00,	00,00,00,00

DD 0x00660033;DB  03,03,00,00,	06,06,00,00
DD 0x00AA0077;DB  07,07,00,00,	10,10,00,00

DD 0x00003737;DB  07,03,07,03,	00,00,00,00
DD 0x0000DDDD;DB  13,13,13,13,	00,00,00,00

DD 0x0000AAAA;DB  10,10,10,10,	00,00,00,00
DD 0x00002222;DB  02,02,02,02,	00,00,00,00

DD 0x00AA00DD;DB  13,13,00,00,	10,10,00,00
DD 0x00660077;DB  07,07,00,00,	06,06,00,00

DD 0x00003333;DB  03,03,03,03,	00,00,00,00
DD 0x00110033;DB  03,03,00,00,	01,01,00,00

DD 0x13131313;DB  03,01,03,01,	03,01,03,01
DD 0x00131313;DB  03,01,03,01,	03,01,00,00

DD 0x77773333;DB  03,03,03,03,	07,07,07,07

DD 0xAAAA0000;DB  00,00,00,00,	10,10,10,10
DD 0xDDDD0000;DB  00,00,00,00,	13,13,13,13

DD 0x00DDDDDD;DB  13,13,13,13,	13,13,00,00
DD 0xDDDDFDA0;DB  00,10,13,15,	13,13,13,13