SignalChapter 10: Meshes

74STAGES

The task

Square X, take 7 away, square that, take 20 away, multiply by 3, and take 1 away.

P must receive the result for each X.

a and d are SC-1s, with MUL at 4 cycles. b is an SC-2L, at 2 cycles an instruction.

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

Split the job, not the stream: each core takes a share of the steps, and the line moves at the pace of its slowest core.

Hints

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

Hint 1Show

Split the job, not the stream: each core does some of the steps to every value.

Hint 2Show

The line moves at the pace of its slowest core, so give each core a fair share of the steps.

Hint 3Show

On an SC-1 a MUL takes 4 cycles; on the SC-2L every step takes 2.

Solution

Reveal the Full SolutionThe complete program for STAGES. 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-1 lite

IN P0
MUL A
OUT P1

bSC-2L low power

IN P0
SUB 7
OUT P1

cSC-2 standard

IN P0
MUL A
SUB 20
MUL 3
OUT P1

dSC-1 lite

IN P0
SUB 1
OUT P1

CYCLES: 287; at par
ENERGY: 2223; at par
NODES: 4; at par
INSTRUCTIONS: 14; at par

Another way: Fast c

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

A only passes values on and c does four steps: a few cycles faster, for more of the work at 2 energy an instruction.

aSC-1 lite

IN P0
OUT P1

bSC-2L low power

IN P0
MUL A
OUT P1

cSC-2 standard

IN P0
SUB 7
MUL A
SUB 20
MUL 3
OUT P1

dSC-1 lite

IN P0
SUB 1
OUT P1

CYCLES: 284; under par
ENERGY: 2340; over par
NODES: 4; at par
INSTRUCTIONS: 14; at par

Another way: Low energy

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

Every step on the 1 energy cores and c only passing values on: the least energy there is, but b's two steps hold the whole line back.

aSC-1 lite

IN P0
MUL A
SUB 7
OUT P1

bSC-2L low power

IN P0
MUL A
SUB 20
OUT P1

cSC-2 standard

IN P0
OUT P1

dSC-1 lite

IN P0
MUL 3
SUB 1
OUT P1

CYCLES: 367; over par
ENERGY: 1872; under par
NODES: 4; at par
INSTRUCTIONS: 14; at par