Fast patterns

Yesterday you counted what a tick costs. Today it is about using less. Three patterns bring the most – and two of them make the code shorter at the same time.

Batch instead of loops#

If twelve corridor lights should do the same thing, you need no loop over twelve names. Give them one name, and one sbn switches them all:

sbn LIGHT HASH("Flur") On dark     # all lights called Flur

One instruction instead of twelve passes of five steps each. A loop only pays off if each device should get something different – like the tank lights from the day before yesterday.

Caching values#

Device values only change once per tick. Whoever reads the same value three times with lbn gets the same number three times and pays three steps. Read it once into a register and keep working there. That saves steps and makes sure all calculations of a tick work with the same value.

Avoiding unnecessary writes#

Many chips write the same value to the same devices every tick. That costs steps – and with some LogicTypes more: command types like Harvest, Plant or Activate trigger their action on every write. Better: remember the last state in a register and only write on a change.

beq dark state start      # nothing changed: do not write
move state dark
sbn LIGHT HASH("Flur") On dark

state starts at −1, a value dark never takes. That guarantees one write on the first pass.