Write assembly for a tiny 8-bit machine. Three scores, no answer to look up.
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Binar.io is an assembly language puzzle game. You are given a machine, a specification, and a blank page.
The BN-8 is an 8-bit processor with two registers, a loop counter, two flags, and twenty-seven instructions. It has no multiplier, no divider, and no compare instruction. Everything it can do, you build out of what it has.
HOW IT WORKS
Each level states a function, not a number. "Return the input with its two nibbles exchanged." "Return 1 when an odd number of the input's bits are set." A byte arrives in register A; whatever is in A when your listing ends is your answer.
Your program is checked against cases you can see and cases you cannot. So there is nothing to write down and nothing to look up. The program has to be right for inputs you were never shown.
THREE KINDS OF PUZZLE
BUILD gives you a blank page and a contract.
REPAIR gives you a listing that is already wrong, and a fault report. The first level in the game is one of these, and the program it hands you passes its first test case on purpose.
IDENTIFY gives you nothing but the cases. Working out what the part is supposed to do is the puzzle.
THREE SCORES, NOT ONE
Every solution is measured on instructions, cycles, and silicon cost. On the levels that matter these do not agree: the smallest program and the cheapest program are different programs, and you cannot have both.
A working program is always worth a star. Optimising is the reason to come back to a level, never the price of leaving it.
WHAT IS IN IT
36 specifications across three worlds, from a single shift to bit reversal, packed field extraction and the doubling ladder. A warm-up mode with 72 generated levels, each with a proven shortest solution. A one-page instruction reference you can open at any time.
Dry and technical on purpose. No story, no energy timers, no ads, no subscription. World 1 is free, all twelve specifications of it. One purchase opens the rest.
For anyone who likes TIS-100, Shenzhen I/O, or finding out that the thing they built by hand was a single opcode all along.