MEM A000h:8100h - S3 - MEMORY-MAPPED PACKED REGISTERS                           
Size:	80 BYTEs
Access:	Write-Only
Desc:	these registers pack two 16-bit I/O registers into a single DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.
	  for faster writes
Note:	the S3 graphics processor registers can be mapped at either
	  linear 000A0000h or at offset 16M from the start of the linear
	  frame buffer
SeeAlso: MEM A000h:8180h


Format of S3 Trio32/Trio64 packed memory-mapped registers:
Offset	Size	Description	(Table M0057)
8100h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	drawing control: row (low word), column (high word)
		"CUR_X" and "CUR_Y" (see PORTIBM PC Portable (uses same BIOS as XT) 82E8h,PORTIBM PC Portable (uses same BIOS as XT) 86E8h)
8104h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	(Trio64) drawing control: row 2 (low word), column 2 (high word)
8108h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	drawing control: destination Y and axial step constant (low
		  word), destination X and axial step constant (high word)
		(see PORTIBM PC Portable (uses same BIOS as XT) 8AE8h,PORTIBM PC Portable (uses same BIOS as XT) 8EE8h)
810Ch	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	(Trio64 only) destination Y 2 and axial step constant 2 (low
		  word), destination X 2 and axial step constant 2 (high word)
		(see PORTIBM PC Portable (uses same BIOS as XT) 8AEAh,PORTIBM PC Portable (uses same BIOS as XT) 8EEAh)
8110h	WORD	error term (see PORTIBM PC Portable (uses same BIOS as XT) 92E8h)
8112h	WORD	(Trio64) error term 2 (see PORTIBM PC Portable (uses same BIOS as XT) 92EAh)
8114h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	unused??? (would correspond to PORTIBM PC Portable (uses same BIOS as XT) 96E8h)
8118h	WORD	drawing control: command register (see PORTIBM PC Portable (uses same BIOS as XT) 9AE8h)
811Ah	WORD	(Trio64) command register 2 (see PORTIBM PC Portable (uses same BIOS as XT) 9AEAh)
811Ch	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	short stroke (see PORTIBM PC Portable (uses same BIOS as XT) 9EE8h)
8120h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	background color (see PORTIBM PC Portable (uses same BIOS as XT) A2E8h)
8124h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	foreground color (see PORTIBM PC Portable (uses same BIOS as XT) A6E8h)
8128h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	write mask (see PORTIBM PC Portable (uses same BIOS as XT) AAE8h)
812Ch	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	read mask (see PORTIBM PC Portable (uses same BIOS as XT) AEE8h)
8130h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	color compare (see PORTIBM PC Portable (uses same BIOS as XT) B2E8h)
8134h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	background mix (low word) and foreground mix (high word)
		(see PORTIBM PC Portable (uses same BIOS as XT) B6E8h,PORTIBM PC Portable (uses same BIOS as XT) BAE8h)
8138h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	top scissors (low word) and left scissors (high word)
		(see PORTIBM PC Portable (uses same BIOS as XT) BEE8h,#P1047)
813Ch	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	bottom scissors (low word) and right scissors (high word)
		(see PORTIBM PC Portable (uses same BIOS as XT) BEE8h,#P1047)
8140h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	data manipulation control (low word) and miscellaneous 2 (high
		  word) (see PORTIBM PC Portable (uses same BIOS as XT) BEE8h,#P1047)
8144h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	miscellaneous (low word) and read register select (high word)
		(see PORTIBM PC Portable (uses same BIOS as XT) BEE8h,#P1047)
8148h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	minor axis pixel count (low word) and major axis pixel count
		  (high word) (see PORTIBM PC Portable (uses same BIOS as XT) BEE8h,#P1047,PORTIBM PC Portable (uses same BIOS as XT) 96E8h)
814Ch	WORD	(Trio64) major axis pixel count 2 (see PORTIBM PC Portable (uses same BIOS as XT) 96EAh)
8150h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	pixel data transfer (see PORTIBM PC Portable (uses same BIOS as XT) E2E8h,PORTIBM PC Portable (uses same BIOS as XT) E2EAh)
8154h 4 DWORDs	???
8164h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	??? (written by STLTH64.DRV for Win95)
8168h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	(Trio64 only) Pattern Y (low word), Pattern X (high word)
		(see PORTIBM PC Portable (uses same BIOS as XT) EAE8h,PORTIBM PC Portable (uses same BIOS as XT) EAEAh)
816Ch	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	??? (written by STLTH64.DRV for Win95)
Note:	setting 8138h to 0 and 813Ch to 12345678h may be a magic value to unlock
	  some S3 features
SeeAlso: #M0073,#M0070