Re: [not quite an RFC] shared bytecode/optree

[Nicholas Clark]

On Wed, Oct 25, 2000 at 11:45:54AM -0400, Chaim Frenkel wrote:
> I vaguly can see a TIL that uses machine code linkage (real machine code
> jumps) that perhaps could use relative addressing as not needing
> relocation. But I'm not sure that all architectures support long enough
> relative jumps/calls.

Specific example where you can't:
on ARM, the branch instructions (B and BL) are PC relative, but only have
a 24 bit offset field. The address space is (now) 32 bit, so there's parts
you can't reach without either calculating addresses (in another register)
and MOVing them to the PC, or loading the PC from a branch table in memory.

Nicholas Clark