romcc progress.

Eric W. Biederman ebiederman at
Tue Jun 10 21:06:01 CEST 2003

I have just implemented inline assembly 
and a better allocator in romcc.

It will now use sse and mmx registers when you give
it the appropriate -mcpu= option.  I am not happy with
the command line options but fixing them is easy.

In addition the quality of the register allocations has improved
to the point that it looks quite a bit like it was done by
hand.  There are limits but there are fewer stupid things happening.

The inline assembly is syntactically the same as gcc's.  But
it is not 100% compatible with gcc.  The goal is to be as compatible
with gcc as gcc is compatible with gcc between ports.  In practice
this means that romcc supports a subset of what gcc does on x86, with
respect to constraints. 

On inline assembly versus builtin operations.  A compiler has a lot
more potential to optimize code in a builtin so I will continue to
implement builtins.  Support wise inline assembly with parameters is a
pain to initially implement but there really is not a support burden
after that.  And there are some operations where there is not gain
making them a builtin.

The code is now checked into the freebios2 tree.  And I can get back
to exercising romcc by writing code with it.


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