ack/plat/pc86
David Given 5bae29a00c ego now builds and is used.
This needed lots of refactoring to ego --- not all platforms have ego descr
files, and ego will just crash if you invoke it without one. I think originally
it was never intended that these platforms would be used at -O2 or above.

Plats now only specify the ego descr file if they have one.
2016-08-21 22:01:19 +02:00
..
include Wasn't exporting the plat headers; refactor to make this a little cleaner. 2016-08-14 11:01:36 +02:00
libsys Fix dependency error (only shows up with make, not ninja. Odd). 2016-08-15 00:46:43 +02:00
.distr Update distribution files. 2013-05-15 23:46:15 +01:00
boot.s Allow pc86 bootloader to boot from more floppy drives. 2012-09-23 14:43:22 -04:00
build-pkg.lua Turns out I wasn't building the syscall libraries. Do so. 2016-08-14 11:23:57 +02:00
build-tools.lua Biggish refactor to break cycles; my build rules were full of them. cpm builds, 2016-08-14 01:39:40 +02:00
build.mk Top, topgen, aelflod. Moved the libraries back into the platform-specific 2013-05-13 23:26:15 +01:00
descr ego now builds and is used. 2016-08-21 22:01:19 +02:00
README Documented floating-point status. 2007-04-28 22:34:47 +00:00

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


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.

IEEE floating point is available, but requires an FPU.

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