Format of Phar Lap real-mode interrupt parameter block:
Offset	Size	Description	)
 00h	WORD	interrupt number
 02h	WORD	real-mode DS value
 04h	WORD	real-mode ES value
 06h	WORD	real-mode FS value
 08h	WORD	real-mode GS value
 0Ah	DWORD	real-mode EAX value
 0Eh	DWORD	real-mode EDX value
Note: all other real-mode values set from protected-mode registers