Assembly Language Help (alang.hlp) (Table of Contents; Topic list)
Important Notice
The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
ROM Locations
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  Address
  (hex)       Size     Description
 
  F000:E000   Varies   BIOS copyright notice.
 
  F000:FFFE   1 byte   System model code.
 
  F000:FFFF   1 byte   System submodel code. The model/submodel
                       codes identify system as follows:
 
                                               Model   Submodel
                       Machine                 Byte    Byte
 
                       PC                      FFh
                       PC/XT (11/08/82 BIOS)   FEh
                       PCjr                    FDh
                       PC/AT (6/10/85 BIOS)    FCh     00h
                       PC/AT (11/15/85 BIOS)   FCh     01h
                       PC/XT-286               FCh     02h
                       PS/2 Model 50[Z]        FCh     04h
                       PS/2 Model 60           FCh     05h
                       PC/XT (1/10/86 and      FBh     00h
                              5/9/86 BIOS)
                       PS/2 Model 30           FAh     00h
                       PC Convertible          F9h     00h
                       PS/2 Model 80 (16MHz)   F8h     00h
                       PS/2 Model 80 (20MHz)   F8h     01h
                       PS/2 Model 70 (20MHz)   F8h     04h
                       PS/2 Model 70 (16MHz)   F8h     09h
                       PS/2 Model 55           F8h     0Ch
                       PS/2 Model 70 (25MHz)   F8h     0Dh
 
  NOTE: These bytes should be used with care, since they may not be
        correct for alternate processor cards (such as Microsoft MACH20),
        software emulators, or other nonstandard configurations.
                                    -♦-