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test(v4.0.0): execute LSHIFT and RSHIFT on the golden model

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Both run exactly as written in DECOMPOSITION.md 5.5 and need no change.
Checked against C on the edge vectors for every count 0 .. N (a count
of N gives 0), at 32- and 64-bit cells, optimised and ASan+UBSan
(`make test`, `make sanitize`). Removing RSHIFT's sign-bit mask fails.

Headroom (data under args / return): 7/5 each.

They are dependencies of C@ and C!, which the pictured-output hold
buffer needs.

Test results on the amd64 host only. This is a development check, not
acceptance (JUSTIFICATION.md section 16).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
rajames
2026-10-03 11:10:03 -04:00
co-authored by Claude Opus 5.5
parent 13ec4b1b6c
commit f030edcd08
2 changed files with 44 additions and 3 deletions
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docs/v4.0.0/DECOMPOSITION.md
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@@ -379,8 +379,8 @@ Section numbers match the v3 primitive reference.
| `OR` | CAP | §4 |
| `INVERT` | OP | `inv` |
| `NOT` | CAP | `0=` (FORTH-79 logical not, as in v3) |
| `LSHIFT` | CAP | `BEGIN dup WHILE 1- SWAP 2* SWAP REPEAT drop` |
| `RSHIFT` | CAP | `BEGIN dup WHILE 1- SWAP 2/ MSB inv and SWAP REPEAT drop` (clears the sign bit each step; `MSB` is the cell-width top-bit constant) |
| `LSHIFT` | CAP | `BEGIN dup WHILE 1- SWAP 2* SWAP REPEAT drop` — executed on the golden model (2026-10-03). |
| `RSHIFT` | CAP | `BEGIN dup WHILE 1- SWAP 2/ MSB inv and SWAP REPEAT drop` (clears the sign bit each step; `MSB` is the cell-width top-bit constant) — executed on the golden model (2026-10-03). |
| `0=` `0<` | CAP | §4 |
| `0<>` | CAP | `0= 0=` |
| `0>` | CAP | `dup 0< SWAP 0= OR 0=` (correct for the most negative number) |