IBM PC CONVERTIBLE Technical Reference page 206

System Power Off Services
(SYS_POWER_OFF)
0298
0298
029A
029C
02Al
02Al
02A6
02A9
02AB
02AC
02AE
02BO
02B2
02B4
02B6
02B8
02BA
02BD
02BF
02CO
02Cl
3C 01
75 05
I NT ISH
ROUTINE-NAME: SYS_POWEILOFF (AH
=
42H)
FUNCTION: THIS ROUTINE POWERS THE SYSTEM DOWN BY THE REQUEST OF THE
APPLICATION PROGRAM. IF WARM START WAS SELECTED THE PGM
WILL RESUME IN THIS ROUTINE AND RETURN TO THE CALLER.
INPUT: AL
=
00 FOR IPL/RESUME DETERMINED BY PROFILE
AL
=
01 FOR RESUME MODE FORCED
OUTPUT: THE SYSTEM IS POWERED OFF. IF SYS SUCCESSFULLY SUSPENDED,
THIS ROUTINE WILL RETURN CONTROL TO THE USER WHEN THE POWER
IS RE-ACTIVATED.
REGISTERS
MODIFIED: AX
SYS_POWEILOFF PROC NEAR
CMP AL,OI REQUEST FOR RESUME MODE?
JNE SYS_POFFl
80 OE 0016 R 40 OR
BIOS_STATUS, F _RESUME
SET FORCE RESUME FLAG
SYS_POFFI :
80 26 003F R CO AND
MOTOR_STATUS,OCOH
RESET DISKETTE MOTORS
BA 03F2 MOV OX, 03 F2H
BO 04 MOV AL,04H TURN OFF MOTORS/SELECT
EE OUT DX,AL
E4 7F IN AL, PWR_STAT ENSURE SUSPEND NMI ENABLED
24 F7 AND
AL,NOT HDWR_RESET
TURN OFF RESET FLAG
OC 04
OR
AL,EN_SUS_NMI
E6 7F
OUT
PWR_STAT ,AL
EB 00
JMP $+2 DELAY
OC 02
OR AL, REQ_POFF REQUEST SYSTEM POWER OFF
E6 7F
OUT
PWR_STAT ,AL
B9 0102
MOV
CX ,MS_D ELA Y
DELAY 1 MSEC
E2 FE
LOOP $
POWER HAS BEEN RESTORED
F8 CLC SET GOOD RETURN
C3 RET
SYS_POWER_OFF
ENDP
ROM BIOS 2-181