HP Vectra Technical Reference Manual page 285

HANDLE_ERRORS:
MOV
MOV
MOV
INT
JC
MOV
MOV
MOV
MOV
SWITCH_STATE,AL
AH, F15-.JOYSTICK
OX,
01
INT_SYSTEM
HANDLE_ERRORS
STICK1-.X, AX
STICK
1_
Y, BX
STICK2-.X, CX
STICK2_Y, OX
,. Save the state of the switches
,. Bits
7..4
in AL.
,. Call it again for joystick info
,. Save x and y position for both
,. joysticks.
,. Continues normally here
,. Error handler here
This subfunction gets called by the keyboard interrupt handler (INT 9H) whenever the user
presses the
<
Sys req> key. Currently the routine just returns but an application can trap this
function to detect when the user presses this key.
On Entry: AH
=
F15_SYS_REQ (85H)
AL
=
00, If user pressed the
<
Sys req> key down (make).
01, If user let go of the
<
Sys req> key (break).
On Exit: No values returned.
Registers Altered: None.
Example: Link into the current
<
Sys req> handler so that it prints "HELLO" everytime the
<
Sys req> key is hit.
INITIALIZA TION_CODE:
MOV
MOV
INT
MOV
MOV
MOV
MOV
276 System Drivers
AH,35H
AL, INT_SYSTEM
21H
OLD_SEG, ES
OLD_OFFSET, BX
AH,25H
AL, INT_SYSTEM
" Get the old INT 15H
" Get CS:IP of INT 15H
,. This MSDOS Int does the work
,. Replace old INT 15H with
,. our routine