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- Subject: Re: VM compilation question
- From: Norman Ramsey <nr@...>
- Date: Thu, 22 Jul 2021 10:41:07 -0400
> > Hmmm. Did that change add much complexity to the compiler? In
> > particular, the logic in the compiler that has to fall back on a
> > multi-instruction sequence when the number of constants is large?
> It does add complexity, but not in that part. The complexity comes
> because now there are several different kinds of operands and
> instructions for one same operation. For instance, a sum can be
> coded with OP_ADD (two registers), OP_ADDI (a register plus an
> immediate small integer), and OP_ADDK (a register plus a constant
> in the contant table).
Oh, that sounds like a noticeable change all right. Reminds me just a
little of generating code for MIPS---similar issues with a 32-bit
I'm curious about the impacts on code size and run time. And which
opcodes are worth ramifying in this way. I imagine that ADD and the
comparisons would get most of the low-hanging fruit.
Will there be a paper forthcoming?