SignalChapter 8: Scarcity

58LITE

The task

P must receive 8 times each X value.

b is an SC-1, a lite core: it has only register A and 8 lines, with no B or XCH.

An SC-1 spends 1 energy an instruction, half of what a standard core like a spends.

The board

The board as the puzzle screen lays it out. Cyan pins read, lemon pins write, violet pins go both ways. On a narrow screen, scroll the board sideways to see all of it.

Key idea

The SC-1: register A only, 8 lines, 1 energy an instruction, no B or XCH; work belongs on the cheap core.

Hints

Each hint goes a step further than the one before. Open them one at a time.

Hint 1Show

An SC-1 is cheap: the same work costs half the energy on b that it costs on a.

Hint 2Show

ADD A doubles A, so three of them in a row multiply by 8.

Hint 3Show

Splitting the work between a and b runs faster, but it costs more energy.

Solution

Reveal the Full SolutionThe complete program for LITE. Open it only when you want the answer.

The reference program

The game's own solution. It passes every test and scores exactly par on every benchmark.

aSC-2 standard

IN P0
OUT P1

bSC-1 lite

IN P0
ADD A
ADD A
ADD A
OUT P1

CYCLES: 237; at par
ENERGY: 1053; at par
NODES: 2; at par
INSTRUCTIONS: 7; at par

Another way: Split

A second program that also passes. It beats par on CYCLES and gives some back on ENERGY.

A doubles once and b twice, so neither core holds up the other. Fewer cycles than par, but the doubling on a costs twice the energy.

aSC-2 standard

IN P0
ADD A
OUT P1

bSC-1 lite

IN P0
ADD A
ADD A
OUT P1

CYCLES: 199; under par
ENERGY: 1170; over par
NODES: 2; at par
INSTRUCTIONS: 7; at par

Another way: Work on a

A second program that also passes, by a different road, at a cost on ENERGY.

All the work on the standard core. It passes, at more energy.

aSC-2 standard

IN P0
ADD A
ADD A
ADD A
OUT P1

bSC-1 lite

IN P0
OUT P1

CYCLES: 237; at par
ENERGY: 1404; over par
NODES: 2; at par
INSTRUCTIONS: 7; at par