ack/plat/linux386
George Koehler a585ddf578 Fix parameters of signal handlers for linuxppc.
Linux passes the arguments in registers, but our compiler expects
arguments on the stack.  Signal handlers got garbage instead of the
signal number.  Some handlers, like the one in lang/m2/libm2/sigtrp.c,
need the correct signal number.

I write a "bridge" in PowerPC assembly that moves the arguments to the
stack.  I put the bridge in sigaction(), so I provide a signal() that
calls sigaction().  I remove the *.c glob or wildcard from build.lua,
so linuxppc only compiles its own signal.c, not the other signal.c for
linux386 and linux68k.

My bridge uses sigprocmask(), so I also add sigprocmask().  Because
linux386 and linux68k use globs, they also get sigprocmask().  I sync
the header files so all three Linux platforms declare execve(),
sigprocmask(), and unlink(), but not remove(), because we have
remove() in <stdio.h>.

I am using sigaction.s to test some features that we recently added to
our PowerPC assembler.  These are the "hi16[...]" and "lo16[...]"
syntax, and also the extended names like "beq", "cmpwi", "li", "subi".
2017-01-22 00:52:32 -05:00
..
include Fix parameters of signal handlers for linuxppc. 2017-01-22 00:52:32 -05:00
libsys Fix dependency error (only shows up with make, not ninja. Odd). 2016-08-15 00:46:43 +02:00
tests Enable tests for linux386 via qemu-i386. 2016-11-26 11:58:02 +01:00
boot.s Ensured that _errno is always defined. Rejigged the pc86 boot code so it doesn't always waste 510 bytes of memory. 2007-04-24 19:25:00 +00:00
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 Plats which use aelflod need to depend on it. 2016-11-26 12:07:08 +01:00
descr Fix an issue throughout where B couldn't be built by ackprogram due to symbol 2016-12-29 17:11:53 +00:00
README Documented floating-point status. 2007-04-28 22:34:47 +00:00

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


The linux386 platform
=====================

linux386 is an i386-based BSP that produces Linux ELF executables.

This port only implements a very limited number of system calls; basically,
just enough to make the demo apps run. Adding more is easy, but there are some
subtleties that require more thought. The port should be considered only in
proof-of-concept stage right now.

Important note: you *can't* link access ELF shared libraries from these
executables. In other words, you have to all your work from inside ACK.

IEEE floating point is available, but requires an FPU.

The executables are generated with aelfslod and are extremely simple; there's
one rwx ELF section which contains all the application's code and data. This
is not optimal, but it does work.


Bugs
====

isatty() is a stub and always returns 0.


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

ack -mlinux386 -O -o linux386.exe examples/paranoia.c

The file linux386.exe can then be run on a i386 Linux machine (or on an
emulation thereof).


David Given
dg@cowlark.com