# GOLEM's VM

GOLEM should compile to *something*, and bytecode seems to be the most
appropriate for various reasons, including portability and longevity.

This VM (and GOLEM in general) won't be optimisation beasts, but they will be
functionnal and if a need to make a large GOLEM program faster comes up in the
future it will be certainly doable by writing a custom compiler. Consider this
to be a reference implementation.

## gyte size

GOLEM bytes will be called gytes to avoid any confusion. Bytes in this document
will refer to 8 bits.

Gyte size could be program specific or fixed.

## header

1 byte will contain gyte size.

1 gyte will contain static data size.

Static data will be stored in the header and will be loaded at the start of the
VM memory.

## memory

GOLEM needs two memory regions:
* the stack for small volatile data
* the heap for allocated, large or long lasting data

Memory sizes should be specified to the VM.

## VM stacks

GOLEM will have two stacks (to not counfound with memory stack):
* the instruction stack to be used by instructions and immediate operations
* the return stack used to store the program counter on function call and
restore it on return