INT 15 - Advanced Power Management Specification - GET POWER STATUS
AX = 530Ah
BX = 0001h
Return: CF clear if successful
BH = AC line status
00h off-line
01h on-line
FFh unknown
other reserved
BL = battery status
00h high
01h low
02h critical
03h charging
FFh unknown
other reserved
CL = remaining battery life
00h-64h (0-100) percentage of full charge
FFh unknown
CF set on error
AH = error code (09h) (see AX=5300h)
Note:   should not be called from within a hardware interrupt handler to avoid
reentrance problems


15530ABX0001 - Advanced Power Management Specification - GET POWER STATUS