INT 15 - Advanced Power Management v1.1 - OEM APM INSTALLATION CHECK

	AX = 5380h
	BH = 7Fh
Return: CF clear if successful
	    BX = OEM identifier
	    all other registers OEM-defined
	    ---Intel SL Enhanced Option BIOS---
	    BX = 534Ch ('SL')
	    CL = 4Fh ('O')
	    AL = version (10h = 1.0)
	    ---HP APM BIOS---
	    BX = 4850h ('HP')
	    CX = version (0001h)
	CF set on error
	    AH = error code (03h) (see #00473)
SeeAlso: AX=5380h/BH=00h