Re: Target machine for compiler course

Mike.Spivey@comlab.oxford.ac.uk (Mike Spivey) writes:
>It might be nice to generate code for the SPARCstations that my
>students will use for their practicals. But isn't generating code for
>RISC machines with register windows, delay slots, etc. too much for a
>first detailed look?


Register windows aren't any more complicated to handle than the need to
save and restore registers on other archictectures. A save as the
first instruction of each function, and a restore in the delay slot of
the ret instruction. Put them together as instructions which always go
in pairs.


Delay slots can easily be handled simply by putting in a nop after
every instruction that has one. The code thus generated is obviously
not very good, but in a course where any machine code that works is
good code, it's a first step.


But on the SPARC stay away from floating point in a short course.
Passing them in int-regs and moving them to float-regs thru memory is
rather messy. It's better to spend course time on something else.
Like pointer variables.
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