Was only used for OP_PUSH data types anyway, so is essentially
useless. Only OP_PUSH has operands after it that directly relate to
it: the rest either have a fixed type (a byte for registers, for
example) or NIL (because they have no operand).
Uses the stack and register, respectively, to jump to an absolute
address. The stack based jump pops a word off the stack to perform a
jump, while the register based one uses the operand to figure out
which register to use.
Registers are now just words, with pushing from and moving to
registers with specified subtypes just pushing those types into the
word registers. That means there are 8 word registers which can act
as 16 half word registers, which themselves can act as 64 byte
registers.
Uses some bit hacks to quickly check what data type an opcode may have
by shifting down to units then casting it to a data_type_t.
Not very well tested yet, we'll need to see now.
