Bytecode Format: A Real Compile Artifact

  • Derive BC1 sections and quote-safe instruction lines.
  • Distinguish structural round trips from runtime validity.
  • Design malformed-artifact tests and deterministic output checks.
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Readiness

  • Read v2 Bytecode and execute named CALL instructions.
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Worked reconstruction

A function plus its call can be represented as:

BC1
FUNC difference a b
LOAD a
LOAD b
SUB
RETURN
END
MAIN
PUSH_NUM 9
PUSH_NUM 2
CALL difference 2
END

The function's code and Main each have their own zero-based instruction coordinates. FUNC and END are format delimiters, not VM instructions. Adding a comment line does not shift an instruction jump target. Running this hand-authored Main returns 7 because it has no final POP.

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Diagnose before implementing

A decoder counts every text line when interpreting JUMP 4. Adding a comment changes execution even though the decoded instructions are otherwise identical. What coordinate system was confused?

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Independent transfer

Write a BC1 string containing a quoted space, escaped quote, and newline escape. Predict the decoded string, then corrupt exactly one delimiter. Compare structural round-trip checks with an independent runtime expected value.

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Carry forward

Carry an encoded artifact and a malformed counterpart into the v2 capstone. The VM must be able to run a decoded copy without any AST or parser state.

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