Sven Barth wrote:
Am 08.02.2012 15:16, schrieb rvmart...@ntlworld.com:
Hans-Peter Diettrich<drdiettri...@aol.com> wrote the following on
08/02/12 11:28:49:
Mark Morgan Lloyd schrieb:
Hans-Peter Diettrich wrote:
steve smithers schrieb:
Regardless of what you may believe, FreePascal is not the first
compiler to be
implemented on 370 architecture.
I.e. you can study how they create code, before you reinvent the wheel
:-)
:-) Had occurred to me as well, although obviously a lot is dictated by
FPC's higher-level parsing and structure.
This should not be a problem. It's up to the code generator to define
its own strategies for allocating space for code and data items, and how
to address them in generated code. The parse tree tells the back-end
*what* should be done, the back-end then has to know *how* to do it.
Might still be very useful for
getting calling conventions etc. right.
The implementation of calling conventions is up to the code generator as
well. You can invent your own conventions, and map them to any
predefined one. As a starting point it's sufficient to support only one
calling convention, the one for system calls. More conventions for
calling other external libraries may be required, depending on the
target OS conventions.
Where can I find details of the input to the back-end?
I'd like to have a crack at generating assembler code for VM/SP.
Best (and AFAIK only) available source: the compiler's source code. Sorry.
I think that that's one of the things that Paul Robinson was trying to
write up: the overall collection of files and how they related to each
other. It's also something that I started working through with regards
to the MIPS backend, and I suspect that there might have been others.
My understanding is that as far as the compiler is concerned almost of
the CPU-specific stuff is in e.g. ./compiler/mips. There are obviously
other things e.g. in the makefiles that glue a particular target into
the overall framework, but once those are in place the developer(s)
working on a particular target are nicely fenced off (for their own
protection, as much as everybody else's :-)
One thing that could be useful: is it possible to build a compiler with
a dummy backend? In other words, such that it can emit all of the node
information (fpc's -an option) even though it doesn't generate any code?
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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