44 lines
1.6 KiB
Markdown
44 lines
1.6 KiB
Markdown
# compare/ — backend output side-by-side with Calypsi 5.16
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Each test case lives as three files:
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- `<name>.c` — the C source.
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- `<name>.ours.s` — our backend's assembly (`clang --target=w65816 -O2 -S`).
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- `<name>.calypsi.lst` — Calypsi's listing file with source, hex bytes, and asm
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in one document (`cc65816 --speed -O 2 --64bit-doubles`).
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Calypsi's `--output` flag emits an ELF object, not text — its `--list-file` is the
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human-readable artifact. (32-bit-doubles is Calypsi's default; we pass
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`--64bit-doubles` so FP-heavy tests compare apples to apples against our IEEE-754
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`double` ABI.)
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## Regenerating
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```
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bash compare/regen.sh
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```
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Recompiles every `*.c` in this directory under both compilers and prints an
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instruction-count summary:
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```
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test ours calypsi ratio
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---- ---- ------- -----
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evalAt 472 254 1.86x
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mul16to32 1 4 0.25x
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sumSquares 26 31 0.84x
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```
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(Numbers above are current as of 2026-05-20 — re-run for latest.)
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## Adding a new comparison
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Drop a `<name>.c` in this directory and run `regen.sh`. No other wiring needed.
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## Counting methodology
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The summary counts asm-line opcodes (lda/sta/jsl/...) on our side and listing
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lines that begin with a hex byte (Calypsi's emit-byte column) on theirs.
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Both metrics are static instruction counts, NOT bytes. They underestimate
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calls-to-runtime (each libcall counts as one `jsl`, not the body it expands to).
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For cycle counts, use `scripts/benchCycles.sh`.
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