Adding better 68040 support to gcc
	----------------------------------

	The 68040 has new opcodes, some of which - like move16, should
be quite useful. The 040 also has a different FPU, so some 68881/2
opcodes run much slower. Gcc-2.3.x understands the 68040, but needs to
know you want 040 specific code. Worse, the most wide spread version
of gas, gas-1.38, does not understand 040 opcodes.

	Obviously the first thing to do is to get a gas that knows
about 040s, such as gas-2.0. Build this version and slip it into place
of your existing gas binary.

	The next trick is to get gcc to generate 040 specific code.
This is quite simple. Generate a specs file for your gcc if don't have
one already. This is done by going into the directory where your
copies of cc1, cc1plus, etc. live and running:

	gcc_for_68k -dumpspecs > specs

Now you can edit the specs file to add 040 support.

At our site the installed base is a mix of 020s, 030s and 040s. To
make it easy to maintain the 020/030 makefiles until the day they all
pass away, we changed the asm & cpp lines to default to 020 mode
unless specified:

*asm:
%{m68000:-mc68010}%{mc68000:-mc68010}%{m68040:-mc68040}%{mc68040:-mc68040}
%{!mc68000:%{!m68000:%{!mc68040:%{!m68040:-mc68020}}}}   %{fpic:-k} %{fPIC:-k}

*cpp:
%{!msoft-float:%{mfpa:-D__HAVE_FPA__ }%{!mfpa:-D__HAVE_68881__ }}%{m68000:-D__mc68010__}%{mc68000:-D__mc68010__}%{!mc68000:%{!m68000:-D__mc68020__ }}%{m68040:-D__mc68040__}%{mc68040:-D__mc68040__} %{!ansi:%{m68000:-Dmc68010}%{mc68000:-Dmc68010}%{!mc68000:%{!m68000:%{!mc68040:%{!m68040:-Dmc68020}}}}}

Now a user can compile for an 040 by adding -m68040 or -mc68040 to the
compilation line.

When the day comes that most of our cpus are 040 based instead we
might change this to:

*asm:
%{m68000:-mc68010}%{mc68000:-mc68010}%{m68020:-mc68020}%{mc68020:-mc68020}   %{!mc68000:%{!m68000:%{!mc68020:%{!m68020:-mc68040}}}}   %{fpic:-k} %{fPIC:-k}

*cpp:
%{!msoft-float:%{mfpa:-D__HAVE_FPA__ }%{!mfpa:-D__HAVE_68881__ }}%{m68000:-D__mc68010__}%{mc68000:-D__mc68010__}%{!mc68000:%{!m68000:-D__mc68040__ }}%{m68020:-D__mc68020__}%{mc68020:-D__mc68020__} %{!ansi:%{m68000:-Dmc68010}%{mc68000:-Dmc68010}%{!mc68000:%{!m68000:%{!mc68020:%{!m68020:-Dmc68040}}}}}

*cc1:
%{sun3:} %{target:} %{m68000:-m68010}%{mc68000:-m68010}%{m68020:-m68020}%{mc68020:-mc68020}   %{!mc68000:%{!m68000:%{!mc68020:%{!m68020:-m68040}}}}

Now gcc generates 040 code by default, unless given a -m68020 option.