On Sat, 2003-05-17 at 23:00, Martin Stjernholm wrote:
the mini jit also abstracts both front and backend, it could be entirely possible to make the mono jit execute pike internal opcodes.
Aha, that's what I missed. Then it's suddenly a whole lot simpler. How would it work integration-wise? Would we have to rip out a lot of source from CIL, or is it some kind of yacc-like tool which eats a VM/opcode spec and spits out a custom VM?
the CIL seems to be defined in some XML and transformed to a c-macro definition file via XSL, which is then included in the interpreter. (in ./mono/cil/)
question: wouldn't it safe some memory if the internal struct{}'s were packed and alinged? gcc does this with __attribute(pack) or so.
They are aligned by default. That's the idea at least. Packing them would perhaps save a bit of memory but at the expense of cpu cycles, and memory is typically a less precious resource than cpu time.
In many places the order and sizes are chosen specifically to get both packing and alignment. E.g. in the svalue struct:
struct svalue { unsigned INT16 type; unsigned INT16 subtype; union anything u; };On a typical 32 bit architecture this takes two 4-byte words: type and subtype shares the first and the other holds the union (which is an integer, float or a pointer to something). If the compiler doesn't pack this by default it probably has a good reason for it.
allright, i see. thx for the enlightenment.
/ karl