bytecode

// source
z = 100
x = 4
y = 10
x = x + y
z = z + y

// stack based:
push 100
push 10
dup
push 4
add
add
// => 6 instruction fetces (costy)
// => (+ 1 4 1 4 1 1 4 1 1) => 18 size in bytes
// we can replace {add,add} with n-add like:
n-add 2
// then it will take 5 fetches, but byte size will be 20

// register based:
// z:0, x:1, y:2
n-set-const {
  i(0 100)
  i(1 4)
  i(2 10)
}
n-left-add {
  i(1 2)
  i(0 1)
}
// => 2 instruction fetches (cheaper)
// => (+ 1 1 4 4 1 4 4 1 4 4 1 1 4 4 1 4 4) 47 size in bytes
//       o t i i t i i t i i o t i i t i i
// o -- operation byte
// t -- operand types descriptor
// i -- int32 operand