ack/plat/linux68k
George Koehler e867861f6d Add 8-byte long long for linux68k.
Add rules for 8-byte integers to m68020 ncg.  Add 8-byte long long to
ACK C on linux68k.  Enable long-long tests for linux68k.  The tests
pass in our emulator using musahi; I don't have a real 68k processor
and haven't tried other emulators.

Still missing are conversions between 8-byte integers and any size of
floats.  The long-long tests don't cover these conversions, and our
emulator can't do floating-point.

Our build always enables TBL68020 and uses word size 4.  Without
TBL68020, 8-byte multiply and divide are missing.  With word size 2,
some conversions between 2-byte and 8-byte integers are missing.

Fix .cii in libem, which didn't work when converting from 1-byte or
2-byte integers.  Now .cii and .cuu work, but also add some rules to
skip .cii and .cuu when converting 8-byte integers.  The new rule for
loc 4 loc 8 cii `with test_set4` exposes a bug: the table may believe
that the condition codes test a 4-byte register when they only test a
word or byte, and this incorrect test may describe an unsigned word or
byte as negative.  Another rule `with exact test_set1+test_set2` works
around the bug by ignoring the negative flag, because a zero-extended
word or byte is never negative.

The old rules for comparison and logic do work with 8-byte integers
and bitsets, but add some specific 8-byte rules to skip libem calls or
loops.  There were no rules for 8-byte arithmetic, shift, or rotate;
so add some.  There is a register shortage, because the table requires
preserving d3 to d7, leaving only 3 data registers (d0, d1, d2) for
8-byte operations.  Because of the shortage, the code may move data to
an address register, or read a memory location more than once.

The multiplication and division code are translations of the i386
code.  They pass the tests, but might not give the best performance on
a real 68k processor.
2019-09-24 13:32:17 -04:00
..
emu Remove extra #include <stdio.h> to fix uint 2018-06-10 16:24:35 -04:00
include All the Linux include directories are the same, so common them all out into a 2018-06-24 19:57:43 +02:00
libsys All the Linux include directories are the same, so common them all out into a 2018-06-24 19:57:43 +02:00
tests Add 8-byte long long for linux68k. 2019-09-24 13:32:17 -04:00
boot.s Ensure that procedure labels are word aligned (required by the EM spec). 2019-06-17 22:26:31 +02:00
build-pkg.lua linux68k builds now. 2016-08-14 11:34:18 +02:00
build-tools.lua Plats which use aelflod need to depend on it. 2016-11-26 12:07:08 +01:00
descr Add 8-byte long long for linux68k. 2019-09-24 13:32:17 -04:00
README Add missing linux68k platform and liblinux support library. 2013-05-09 00:56:10 +01:00

# $Source: /cvsroot/tack/Ack/plat/linux386/README,v $
# $State: Exp $
# $Revision: 1.2 $


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