HP Vectra Technical Reference Manual page 313

Makes a sound as defined by the current values of T_SND_BEEP_CYCLE and
T_SND_BEEP_DURA in the EX-BIOS data area.
On Entry: BP
=
V_SYSTEM (12H)
AH
=
F_SND_BEEP (3AH)
On Exit: AH
=
Return Status Code
Registers Altered: AH, BP, DS
Defines beep frequency and duration.
On Entry: BP
=
V_SYSTEM (12H)
AH
=
F_SND_SET_BEEP (3CH)
BX
=
Frequency 1 to 25000 hz.
If (BX)
=
0 then tone off.
DX
=
duration of tone in 10 microsecond increments
On Exit: AH
=
Return Status Code
Registers Altered: AH, DS, BP.
Example: Set Beep frequency to 660 Hz for duration of 1/2 second.
MOV
MOV
MOV
MOV
PUSH
INT
POP
BP, V_SYSTEM
AH,F-:..-SNO_SET_BEEP
BX,660
OX, 50000
OS
HP_ENTRY
OS
,. HP vector 12H
,. function 3CH
,. Frequency in hertz
,. 1/2 a second in 10
,. microseconds increments.
,. EX-BIOS destroys OS
,. Int 6FH for EX-BIOS
Generates a tone of the given frequency and duration with an approximate 0.5 percent error.
304 System Drivers