Re: [Tack-devel] arm and powerpc assembly

[David G. <dg...@co...>]

David Given wrote:
[...]
> I'd also modified aelflod to generate non-386 ELF files, but George
> Koehler's patch was better than mine so I've replaced it with his. The
> linux386, linuxppc and linux68k platforms all now generate executables.

I've merged all this into trunk (except the stack offset changes in the
code generator). linux68k is enabled by default.

linuxppc is *not* enabled by default. It turns out that when compiling
the code generator table for PowerPC, ncgg repeatedly errors out with:

    Previous rule impossible on empty stack

One of the rules that's causing this is as follows:

        pat adf $1==INT32                  /* Add single */
                with FS FS
                        uses reusing %1, FREG
                        gen
                                fadds {FS, %a}, %2, %1
                        yields {FS, %a}

(The full file is here:
http://tack.hg.sourceforge.net/hgweb/tack/tack/file/4fe6836f55cb/mach/powerpc/ncg/table)

It would seem that back when I was doing all this, I managed to work
around the error by simply commenting out the code that makes the error
in ncgg!

I don't actually know what the error means. I assume it's something to
do with the contents of the fake stack. But I don't know why having the
fake stack be empty is a problem --- surely the code generator would
just coerce values onto it if needed?

I realise that the number of people who still know about this level of
detail is approximately nil, but... any suggestions?

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