Hardware Interrupts; Device Details - Husky MP2500 Manual

31.3 Hardware interrupts

The MP2500 design includes the normal hardware interrupts, vectors and
service routines for an IBM PC. For detailed lists, see section 19.1. For
more detailed information, refer to standard texts on IBM PC hardware.
The design also includes a number of interrupts that are not present in an
IBM PC, which are mainly concerned with the special requirements of a
portable computer. Since MP2500 is not designed for internal expansion by
third parties, the details of these interrupts are irrelevant to most third
parties and will not be covered here. For details contact H
Application programs can trap hardware interrupts (and other interrupts) by
changing the vectors to point into their own code. For details, see section
19.1.
CAUTION: YOU MUST NOT CHANGE VECTOR 02H, which is
responsible for servicing NMIs, as NMIs are vital to
operation of MP2500. If you change this vector,
MP2500 will cease to operate. YOU HAVE BEEN
WARNED.

31.4 Device details

As already mentioned, to be considered IBM PC-compatible, a computer
must use the same devices, or emulate them. MP2500 mainly takes the
first option. The main exception is the CGA display system, as the devices
used in the IBM PC could not be used to produce a convenient portable
design.
This section describes the behaviour of the CGA emulation and indicates
where its behaviour differs sufficiently to compromise compatibility. Where
a register is described as 'unimplemented', any attempt at access will
simply be ignored.
Note that compatibility extends even to low level access; you are not limited
to access via the BIOS.
For information on the other devices, refer to any standard text on IBM PC-
AT hardware.
Chapter 31: Hardware
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