Question about Machine Description

Ian Lance Taylor iant@google.com
Mon May 3 20:00:00 GMT 2010


yazdanbakhsh <amir.yazdanbakhsh@gmail.com> writes:

> I'm working on my a gcc compiler for my own written processor with the help
> of SimpleScalar.
> I want to remove "srav/slav" (immediate arithmetic shift) from the
> instruction set. I explore ss.md file but I didn't see any define_ins for
> the mentioned instructions, but they are used in other instruction
> definitions.
> It is also exist for addi/addui. Where I can find the definitions of these
> instructions? I want to force gcc to just use register shift and register
> add.

There is no ss.md file in the standard gcc distribution.  If
SimpleScalar has a gcc port, I don't know anything about it.  So it's
hard to answer to your question precisely.

Instructions can come from either a .md file or a .c file in the
config/CPU directory used for your CPU.  If those instructions are
appearing in the generated assembler, then they must be in there
somewhere.

Ian



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