SPC8106 S-MOS Systems, SPC8106 Datasheet - Page 209

• Manufacturer Part Number: SPC8106
• Description: LCD/CRT VGA CONTROLLER
• Manufacturer: S-MOS Systems

7.0
7.1
The BIOS will exist in a 32 KB section of ROM located at C000 or any other configurable location.
Segment references within the code will self define at initialization time, however an initial BIOS
segment must be configured into the ROM image.
The layout of this segment is as follows:
The single segment structure of the BIOS versus a dual image structure (where the Extensions
have their own segment) has the advantage that OS/2 2.0 will work correctly in the virtual DOS
box.
7.2
Some software expects the word 'IBM' to be located at C000:001E to determine if it is running on
an EGA or better. We have initially put the word 'IBM' at this location, but, if the BIOS is relocated
to another segment, E000 for example, software that does check at C000:001E will not work.
There is very little chance of running across current software with this test.
The BIOS will also contain the string “Copyright (c) Seiko Epson Corp. 1987, 1993. All rights
reserved” in two locations. One of these must stay in the code, the other is part of the header that
is displayed on power-up. The power-up string is configurable and can be overwritten by the
OEM.
SPC8106
411-1.0
Initialization
Routine
PHYSICAL LAYOUT OF THE BIOS
Single Segment Structure
IBM Notice, Copyright Notice
S-MOS Systems, Inc. • Tel: [phone] • Fax: [phone] • http://www.smos.com
Function
Dispatch
Function
Calls
Video
Parameter
Table
X12-SP-002-03.1
Character
Fonts
8, 14, 16,
& 18 or 19
if needed
Extensions
Initialization
Extensions
Dispatch
BIOS Functional Specification
Extensions
Function
Calls
Extensions
Parameter
Tables
SP2-39