Echo four bytes

L1.R2.echo-4

Native verification status · ● solved

What this result establishes

Public example suite. Fixed public examples, with exact output and halt required. Canonical copying solutions may be more general than the tested suite; the suite alone does not establish that.

Placement: Verified canonical or tool baseline. Similar slots are retained for historical continuity. How rank is interpreted.

Challenge

ladder rank: #7 (historical identifier L1)
family / transform: EchoPrefix / Identity
cases: 1 case, 4 output bytes each
limits: program ≤ 256 bytes, ≤ 1024 steps/case
task summary: Extend fixed-width copying to four bytes.
exact contract: Registry JSON · L1.R2.echo-4

Harness documentation

Winning program

solutions/echo/echo-4.mal · 9 bytes · sha256 cfded278793852a4bf892de139e3b3cc67680fcc3d822b42f40f6e67bf0dc69a

ubs`q^o\I

Solver

name: HeLL-Lite (tool)
type: tool
harness: tools/hell_lite compile-linear (deterministic straight-line template)
metric: 1/1 case, 5 seeds
attribution notes: First-use opcode encoding of the straight-line IN/OUT sequence; each address has exactly one printable byte per opcode.

Task notes

Extend fixed-width copying to four bytes.

Earlier record notes

Retained for provenance; these notes may predate current calibration. See the verification scope and placement rationale above.

Echo the first 4 input bytes; 9-byte straight-line program.

Verification transcript (native VM, 3 epochs)

epoch 0 · seed b9e8340babf4… · 1/1 cases

case	input	expected	observed	status
0	3f23e18ff46361cc…	3f23e18f	3f23e18f	ok

epoch 1 · seed 7b651b57e150… · 1/1 cases

case	input	expected	observed	status
0	b08354c906af4af1…	b08354c9	b08354c9	ok

epoch 2 · seed 0c4caf1fd38a… · 1/1 cases

case	input	expected	observed	status
0	3c83496cbe618409…	3c83496c	3c83496c	ok

Reproduce

git clone https://github.com/oklo/malbolge-rungs
cargo run -p harness -- verify --rung L1.R2.echo-4 --program solutions/echo/echo-4.mal --epochs 3 --verbose