opcode | instruction | operands (mod 0) | operands (mod 1)
 -------+-------------+------------------+-----------------
 0x00   | jmp         | r1               | r2:r1
 0x01   | movr        | r1, r2           | rx,   imm 
 0x02   | movm        | r1, [ds:r2]      | [ds:r1], r2
 0x03   | add         | r1, r2           | r1,   imm

 flags
 
 cmp r1, r2 instruction results in:
    r1 == r2 => fl = 0
    r1 < r2  => fl = 0xff
    r1 > r2  => fl = 1
 
    jmpe r1
    => if (fl == 0) jmp r1
    else nop