Hi Jakob,

> "64-bit" picolisp also portable to 32-bit CPUs?
> Or would it take a kludge of some sort?

I'm afraid so. In fact, I once started to write "src64/arch/x86-32.l",
but didn't finish it.

It is indeed possible to emulate the 64-bit architecture of the PicoLisp
virtual machine (as documented in "doc64/asm") on hardware with a
smaller word size, but only with a big overhead.

Not only that a lot of space is wasted (double size of each cell). The
hard stuff is calculating the CPU flags (zero, sign and carry)
correctly, as all primitive operations must be emualated in multiple
steps. Also, interfacing to the external world (libc, native calls etc.)
doesn't fit well. Because 32-bit CPUs usually don't have enough
registers, the emulated registers must reside in RAM, further slowing
things down.

Nevertheless, it would be fun ;-)

On the other hand, the C version runs well on 32-bit CPUs. Why would you
like to have the 64-bit version backported? The reason why I started
with "x86-32.l" back then was for testing purposes, but this can be done
as well using qemu.

- Alex
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