Format of HP EX-BIOS Driver Describe Record:
Offset	Size	Description	)
 00h 16 BYTEs	EX-BIOS driver header data (see #03745)
 10h	BYTE	device GID type
		bits 7-4: device type
		bits 3-0: physical device link address
 11h	BYTE	physical device ID (see #03751)
 12h	WORD	logical device status bits (see #03750)
 14h	BYTE	physical device vector number (driver ID / 6)
 15h	BYTE	maximum number of axes reported (0-2)
 16h	BYTE	device class
		bits 7-4: current class
		bits 3-0: default class
 17h	BYTE	number of buttons/prompts
		bits 7-4: number of prompts
		bits 3-0: number of buttons
 18h	BYTE	reserved
 19h	BYTE	(physical devices only) maximum output burst length
 1Ah	BYTE	(physical devices only) number of write registers
 1Bh	BYTE	(physical devices only) number of read registers
 1Ch	BYTE	button transition flags (bit 0 = button0, etc.)
 1Dh	BYTE	current button states (bit 0 = button0, etc.)
 1Eh	WORD	device resolution
 20h	WORD	maximum x-axis count
 22h	WORD	maximum y-axis count
 24h	WORD	X position data for absolute devices
 26h	WORD	Y position data for absolute devices
 28h	WORD	X delta for relative devices
 2Ah	WORD	Y delta for relative devices
 2Ch	WORD	(logical devices only) X-axis scaling accumulator
		(fraction of one logical unit)
 2Eh	WORD	(logical devices only) Y-axis scaling accumulator
		(fraction of one logical unit)