view extra/README @ 507:dd9c5cef2e80 tip

Fix missing extern declaration Variable declarations in headers need to be "extern". Fix missing "extern" in input.h. (Turns it it was there previously and was erroneously removed in a previous clean up patch.) Thank you to John W. Linville <linville@redhat.com> for reporting the problem.
author William Astle <lost@l-w.ca>
date Thu, 06 Feb 2020 15:04:05 -0700
parents 3832a68d83ef
children
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These files are extra utility type scripts that can be used for various
purposes.

as

This is a sort of front-end script that makes lwasm look approximately like
gnu as which is useful for using lwasm as a backend to gcc.  You may need to
edit it to make it work fully.

ld

Similar to the "as" script above except for lwlink.


ar

Similar to the "as" script above except for lwar.

gcc6809lw-*.patch

These are patches to the main gcc source distribution for specific releases. 
The last number after the dash is a patch level for the specific patch. It
is worth noting that a patch for a particular minor version of GCC may work
with later minor versions in the same release sequence. That is, a patch
for 4.6.1 might work with 4.6.4. These are different to the official
gcc6809 releases in the following ways. First, all the source for as-6809
is removed. Also, the special "helper" makefile and directory is removed. 
Also, as of this writing, the latest "official" release was for gcc 4.3.4
which does not build on 64 bit linux.

In the event you have used the "official" gcc6809 with the default as6809
assembler that comes with it, you should be aware that while lwasm is mostly
compatible with it syntax wise, there are differences, particularly in
pseudo operations and source line syntax (most notably that you must have
whitespace preceeding assembler directives and instructions).  You will
likely not run into these unless you are using inline asm. Refer to the
lwtools documentation for the specific line format required by lwasm.

It is worth noting that neither gcc6809 nor lwtools comes with a standard C
library.

It is also worth noting that for many projects, it will be more flexible to
invoke lwlink directly rather than using the ld script or gcc as a front
end. See the lwtools documentation for details on using lwlink.

To use these scripts, you really need to understand how to build a gcc as a
cross compiler. The basics are that you put the as, ld, and ar scripts
whereever you plan to put your cross-development binaries. Then, when
building the cross compiler, you tell it where the scripts are.

Please note that the following recipe is an example only. If you are
planning to install multiple instances of gcc6809 for different targets, you
will most certainly need to modify the steps below. Providing a complete
understanding of building a gcc toolchain for cross compilation is well
beyond the scope of this document.

The following works for a single installation.

1. Install the ar, as, and ld scripts named m6809-unknown-{as,ar,ld} in a
directory in your path, say /usr/local/coco/bin/.

2. Make symbolic links to /bin/true for similarly named nm, objdump, ranlib,
and strip in the same directory  Some of these may not be necessary.

3. Unpack gcc and apply the gcc6809 patch. The gcc6809lw* patch file
in this directory is known to work with these instructions.

4. Make sure /usr/local/coco/bin is in your PATH

5. Make sure "." is NOT in your path or is at the END of PATH. If you have
gazillions of errors pop up compiling "gemodes.c", this is your problem.

6. In a directory (other than the gcc source, say "gcc-build" at the same
level as the main gcc directory, do (assuming gcc 4.3.4):

configure --enable-languages=c --target=m6809-unknown \
--program-prefix=m6809-unknown- --enable-obsolete \
--srcdir=../gcc-4.3.4 --disable-threads --disable-nls \
--disable-libssp --prefix=/usr/local/coco \
--with-as=/usr/local/coco/bin/m6809-unknown-as \
--with-ld=/usr/local/coco/bin/m6809-unknown-ld \
--with-ar=/usr/local/coco/bin/m6809-unknown-ar

NOTE: the last three are required to prevent selection of the wrong binutils
programs at runtime.

--with-sysroot might be useful if you have a C library involved.

7. Run "make". If errors appear, troubleshoot.

8. Run "make install". Note that you will have to have your PATH variable
for "root" set up correctly if your install prefix requires root privileges.

The above is WOMM certified. YMMV.

NOTES ABOUT SPECIFIC PATCHES
============================

Old gcc6809 patches have been removed to avoid confusion.

The -6 patch fixes a code generation ICE. The previous -4 patch fixed a code
generation error that could have a substantial impact. The -3 patch fixed
some compatibilty with new lwtools versions. The -2 patch fixed a major set
of ICEs by completely removing the "soft registers" business. They're
apparently not needed with gcc 4.6.x at all and it's not clear they were
even needed with gcc 4.3.x. They also had the side effect of causing things
to break even if they weren't in use so they had to go. In other words, the
-6 patch is the current best version to use so there's no point including
the old ones.