dtrg e02179a9fe Updated for the 6.0pre2 release. 17 years ago
..
include de5dfda220 Fixed major typos in the signal declarations that was preventing anything that used signal() from compiling. 17 years ago
libsys e02179a9fe Updated for the 6.0pre2 release. 17 years ago
.distr e02179a9fe Updated for the 6.0pre2 release. 17 years ago
README 42c2cdb985 Updated to work with the new libmon-less setup. 17 years ago
boot.s 5621f951a2 Ensured that _errno is always defined. Rejigged the pc86 boot code so it doesn't always waste 510 bytes of memory. 17 years ago
descr 5621f951a2 Ensured that _errno is always defined. Rejigged the pc86 boot code so it doesn't always waste 510 bytes of memory. 17 years ago
pmfile 42c2cdb985 Updated to work with the new libmon-less setup. 17 years ago

README

# $Source$
# $State$
# $Revision$


The pc86 platform
=================

pc86 is an i86-based BSP that produces bootable floppy disk images that can
be run on most PCs. It is intended to be quick and dirty rather than actually
useful, although it may come in handy for hardware test purposes, boot
loaders, and the like.

The code runs in TINY mode, where CS, DS and SS all share the same segment.
This means that there's not very much memory available. It would be very easy
to change it to run in SMALL mode, where CS occupies one segment and DS and SS
another, which would give 64kB for nearly all programs; I just haven't done it.

This port only implements a very limited set of syscalls --- and most of those
are stubs required to make the demo apps link. File descriptors 0, 1 and 2
represent the console. All reads block. There's enough TTY emulation to allow
\n conversion and local echo (but it can't be turned off).


Example command line
====================

ack -mpc86 -O -o pc86.img examples/paranoia.c

The file pc86.img can then be copied onto a floppy and booted, or run via qemu
or somesuch emulator.


David Given
dg@cowlark.com