From cdd4aadccc88dadbdfc664556d6637e6fe0bf140 Mon Sep 17 00:00:00 2001 From: Drew T <50529377+Druthulu@users.noreply.github.com> Date: Wed, 2 Sep 2026 15:57:56 -0600 Subject: [PATCH] =?UTF-8?q?docs(cookbook):=20=C2=A7428a=20sharpened=20?= =?UTF-8?q?=E2=80=94=20break-vs-return=20is=20a=20PER-ARM=20regalloc=20dia?= =?UTF-8?q?l?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit StreamLoadStateMachine (MATCH 459/459) settled the general form of the law S72 found by refutation. 'return 0' keeps the hard-$v0 set live inside that arm and EXCLUDES $v0 from the allocator there; 'break' to a shared post-switch return frees it. Case 11 needs return 0, every other zero-arm needs break — one dial, eleven positions, correct setting is per-arm not global. func_80035C4C is the same pattern from the other side. Completes the ladder: §3-B (fold returns) is the default because it frees the register, §428a explains why the freed resource resolves coupled residuals, and the dial is how you put the pin back where one arm needs it. --- docs/cookbook-index.md | 34 +++++++++++++++++----------------- docs/matching-cookbook.md | 13 +++++++++++++ 2 files changed, 30 insertions(+), 17 deletions(-) diff --git a/docs/cookbook-index.md b/docs/cookbook-index.md index f9a33ef58..0082f3751 100644 --- a/docs/cookbook-index.md +++ b/docs/cookbook-index.md @@ -102,7 +102,7 @@ - **§370** — ★★ — A **HARD BOUND** FROM sched.c, AND THE reorg SLOT-STEAL DIAGNOSTIC (P31 S68; main/func_8001BC6C, 69 ins, NOT closed — 33 → 28 over ~45 measured compiles) L31838 - **§396g** — ★★ — A GUARD LADDER'S RUNGS MUST STAY SYMMETRIC OR `reorg.c` LOSES ITS BRANCH REDIRECT (P31 S69; byte-proven ov_SC03_028/func_80184C90, 92 ins) L32818 - **§428** — ★★★ — A ZERO-BYTE CROSS-JUMP BARRIER: ADVANCE THE POINTER INSIDE EACH SWITCH ARM (P31 S72; `main/func_80026D64`, 218 ins, MATCH in 2 compiles) L33954 -- **§430** — ★★★ — A SHARED TAIL IS A LATE CROSS-JUMP MERGE, NOT A SOURCE `goto` — AND SPELLING IT AS ONE CAN INVALIDATE A LOOP (P31 S72; `main/CdReadSectorReadyCB`, 422/424 ins, verified with `cc1 -dL`) L34027 +- **§430** — ★★★ — A SHARED TAIL IS A LATE CROSS-JUMP MERGE, NOT A SOURCE `goto` — AND SPELLING IT AS ONE CAN INVALIDATE A LOOP (P31 S72; `main/CdReadSectorReadyCB`, 422/424 ins, verified with `cc1 -dL`) L34040 ### instruction scheduling (88) @@ -376,7 +376,7 @@ - **§3-1.** — DEAD-RESET CSE-BREAKER — the zero-footprint replacement for a §195-I asm re-tie L31979 - **§385** — ★★★ — THE **SCHED2 PRIORITY-DONOR ASM**: closing the "hoisted-invariant vs IV-init preheader swap" class (P31 S69; byte-proven main/func_80038A58, 347 ins, fable escalation 2 → 0) L32309 - **§417** — ★★★ — A REGISTER PIN CAN BLOCK `jump.c`'s SELECT COLLAPSE, AND UNPINNING THEN EXPOSES A `cse` SKIP-BLOCKS MERGE (P31 S71; byte-proven `ov_SC03_013/func_8017E6F4`, 182 ins) L33605 -- **§432** — ★★★ — DEFEAT cse's MERGE OF TWO IDENTICAL MASKS BY SPELLING ONE AS A SHIFT PAIR (P31 S72/S73; `main/func_8002DC68`, MATCH 198/198) L34160 +- **§432** — ★★★ — DEFEAT cse's MERGE OF TWO IDENTICAL MASKS BY SPELLING ONE AS A SHIFT PAIR (P31 S72/S73; `main/func_8002DC68`, MATCH 198/198) L34173 ### loops & induction variables (48) @@ -427,7 +427,7 @@ - **§386** — ★★★ — A BYTE LOAD ON THE **BIV** BASE WAS BORN IN THE COMBINE PASS: SPELL IT AS A SHIFT-MASK, NEVER A DEREF (P31 S69; byte-proven main/func_80020598, 292 ins, escalation 1 → 0) L32335 - **§393** — ★★ — THE **BIRTHING BOOST**: A SINGLE-SET LOCAL IS SCHEDULED LAST; GIVE IT A SECOND SET (P31 S69; byte-proven ov_SC02_017/func_8017FCFC) L32543 - **§418** — ★★★ — TWO LOOP-STRUCTURE LEVERS: MAKE THE SECOND INDEX A GIV, AND KEEP A TABLE ADDRESS UNFOLDED (P31 S71; byte-proven `ov_SC04_016/func_8017DF8C`, 184 ins, 32 → 0 in seven compiles) L33632 -- **§430** — ★★★ — A SHARED TAIL IS A LATE CROSS-JUMP MERGE, NOT A SOURCE `goto` — AND SPELLING IT AS ONE CAN INVALIDATE A LOOP (P31 S72; `main/CdReadSectorReadyCB`, 422/424 ins, verified with `cc1 -dL`) L34027 +- **§430** — ★★★ — A SHARED TAIL IS A LATE CROSS-JUMP MERGE, NOT A SOURCE `goto` — AND SPELLING IT AS ONE CAN INVALIDATE A LOOP (P31 S72; `main/CdReadSectorReadyCB`, 422/424 ins, verified with `cc1 -dL`) L34040 ### structs, block moves & memcpy (88) @@ -797,8 +797,8 @@ - **§412** — ★★★ — §323 CARVE BLOCKER 2 WAS A REGEX THAT COULD NOT SEE PAST `__attribute__` (P31 S71) L33424 - **§426** — ★★★ — main's SWITCH FUNCTIONS WERE NEVER A CODEGEN WALL: ONE RODATA CARVE HAD BEEN MISSING SINCE PHASE 7 (P31 S72; 3 of the 11 "PROVEN gate-rejects" banked byte-identical in 14 s) L33855 - **§428** — ★★★ — A ZERO-BYTE CROSS-JUMP BARRIER: ADVANCE THE POINTER INSIDE EACH SWITCH ARM (P31 S72; `main/func_80026D64`, 218 ins, MATCH in 2 compiles) L33954 -- **§431** — ★★★ — SPLITTING A 27,000-LINE TU AT ITS ORIGINAL BOUNDARIES: THE JTBL SPANS TELL YOU WHERE, AND THE COMPILER TELLS YOU WHAT CROSSES (P31 S72; `src/800.c` -> `800.c`/`800_b.c`/`800_c.c`, byte-identical with nothing banked) L34065 -- **§433** — ★★★ — ON A SWITCH FUNCTION, CASE SOURCE ORDER IS THE DOMINANT RESIDUAL — AND `match_one` IS BLIND TO IT (P31 S73; 4 of 5 consecutive main MATCHes) L34128 +- **§431** — ★★★ — SPLITTING A 27,000-LINE TU AT ITS ORIGINAL BOUNDARIES: THE JTBL SPANS TELL YOU WHERE, AND THE COMPILER TELLS YOU WHAT CROSSES (P31 S72; `src/800.c` -> `800.c`/`800_b.c`/`800_c.c`, byte-identical with nothing banked) L34078 +- **§433** — ★★★ — ON A SWITCH FUNCTION, CASE SOURCE ORDER IS THE DOMINANT RESIDUAL — AND `match_one` IS BLIND TO IT (P31 S73; 4 of 5 consecutive main MATCHes) L34141 ### optimisation level (-O0/-O2) (22) @@ -1029,7 +1029,7 @@ - **§3-D.** — INTEGRATION IS STILL THE BOTTLENECK, AND THE TU IS THE AUTHORITY L33140 - **§415** — ★★ — A FILE-SCOPE DECL MAKES gcc-2.7.2 MERGE THE TU'S LATER *BLOCK-SCOPE* EXTERNS INTO IT (P31 S71; byte-proven `ov_SC04_011/func_80180B24`, 215 ins) L33547 - **§423** — ★★★ — "MATCH IN ISOLATION + GATE REJECTS + CAUSE NOT DETERMINED" ⇒ GREP THE TU FOR A FILE-SCOPE TYPEDEF THE DRAFT ALSO CARRIES (P31 S71; byte-proven `ov_SC03_092/func_8017FA74`) L33780 -- **§431** — ★★★ — SPLITTING A 27,000-LINE TU AT ITS ORIGINAL BOUNDARIES: THE JTBL SPANS TELL YOU WHERE, AND THE COMPILER TELLS YOU WHAT CROSSES (P31 S72; `src/800.c` -> `800.c`/`800_b.c`/`800_c.c`, byte-identical with nothing banked) L34065 +- **§431** — ★★★ — SPLITTING A 27,000-LINE TU AT ITS ORIGINAL BOUNDARIES: THE JTBL SPANS TELL YOU WHERE, AND THE COMPILER TELLS YOU WHAT CROSSES (P31 S72; `src/800.c` -> `800.c`/`800_b.c`/`800_c.c`, byte-identical with nothing banked) L34078 ### build graph, splat & the harness (195) @@ -1692,7 +1692,7 @@ - **§3-The** — nine laws this wave produced L33288 - **§413** — ★★★ — DIFFICULTY IS THE RESIDUAL CLASS, NOT `nins` — ROUTE THE MODEL TIER OFF HISTORY (P31 S71, Drew) L33473 - **§416** — ★★ — FOUR LEVERS FROM THE S71 OVERNIGHT LANE, none of which the cookbook held (P31 S71) L33572 -- **§434** — ★★★ — TWO SYMBOLS, ONE FRAME: RUN THE FRAME CHECK BEFORE DRAFTING ANYTHING LARGE (P31 S73; `main/SaveLoadRoutine` + `func_8002B0B4`, byte-verified) L34202 +- **§434** — ★★★ — TWO SYMBOLS, ONE FRAME: RUN THE FRAME CHECK BEFORE DRAFTING ANYTHING LARGE (P31 S73; `main/SaveLoadRoutine` + `func_8002B0B4`, byte-verified) L34215 ## All sections, in order @@ -2794,11 +2794,11 @@ - **§427** — ★★ — A HASH IS A CORRECTNESS ORACLE WITH ZERO DIAGNOSTIC CONTENT; PRESERVE THE RED ARTIFACT BEFORE ANYTHING REBUILDS OVER IT (P31 S72) L33935 - **§428** — ★★★ — A ZERO-BYTE CROSS-JUMP BARRIER: ADVANCE THE POINTER INSIDE EACH SWITCH ARM (P31 S72; `main/func_80026D64`, 218 ins, MATCH in 2 compiles) L33954 - **§428a** — ★★★ — TWO RESIDUALS THAT MOVE IN OPPOSITE DIRECTIONS UNDER EVERY LEVER USUALLY SHARE ONE CAUSE (P31 S72; `main/func_8001B0D4`, NEAR/53 -> MATCH; **my first answer here was WRONG and is kept below as the refutation**) L33992 -- **§430** — ★★★ — A SHARED TAIL IS A LATE CROSS-JUMP MERGE, NOT A SOURCE `goto` — AND SPELLING IT AS ONE CAN INVALIDATE A LOOP (P31 S72; `main/CdReadSectorReadyCB`, 422/424 ins, verified with `cc1 -dL`) L34027 -- **§431** — ★★★ — SPLITTING A 27,000-LINE TU AT ITS ORIGINAL BOUNDARIES: THE JTBL SPANS TELL YOU WHERE, AND THE COMPILER TELLS YOU WHAT CROSSES (P31 S72; `src/800.c` -> `800.c`/`800_b.c`/`800_c.c`, byte-identical with nothing banked) L34065 -- **§433** — ★★★ — ON A SWITCH FUNCTION, CASE SOURCE ORDER IS THE DOMINANT RESIDUAL — AND `match_one` IS BLIND TO IT (P31 S73; 4 of 5 consecutive main MATCHes) L34128 -- **§432** — ★★★ — DEFEAT cse's MERGE OF TWO IDENTICAL MASKS BY SPELLING ONE AS A SHIFT PAIR (P31 S72/S73; `main/func_8002DC68`, MATCH 198/198) L34160 -- **§434** — ★★★ — TWO SYMBOLS, ONE FRAME: RUN THE FRAME CHECK BEFORE DRAFTING ANYTHING LARGE (P31 S73; `main/SaveLoadRoutine` + `func_8002B0B4`, byte-verified) L34202 +- **§430** — ★★★ — A SHARED TAIL IS A LATE CROSS-JUMP MERGE, NOT A SOURCE `goto` — AND SPELLING IT AS ONE CAN INVALIDATE A LOOP (P31 S72; `main/CdReadSectorReadyCB`, 422/424 ins, verified with `cc1 -dL`) L34040 +- **§431** — ★★★ — SPLITTING A 27,000-LINE TU AT ITS ORIGINAL BOUNDARIES: THE JTBL SPANS TELL YOU WHERE, AND THE COMPILER TELLS YOU WHAT CROSSES (P31 S72; `src/800.c` -> `800.c`/`800_b.c`/`800_c.c`, byte-identical with nothing banked) L34078 +- **§433** — ★★★ — ON A SWITCH FUNCTION, CASE SOURCE ORDER IS THE DOMINANT RESIDUAL — AND `match_one` IS BLIND TO IT (P31 S73; 4 of 5 consecutive main MATCHes) L34141 +- **§432** — ★★★ — DEFEAT cse's MERGE OF TWO IDENTICAL MASKS BY SPELLING ONE AS A SHIFT PAIR (P31 S72/S73; `main/func_8002DC68`, MATCH 198/198) L34173 +- **§434** — ★★★ — TWO SYMBOLS, ONE FRAME: RUN THE FRAME CHECK BEFORE DRAFTING ANYTHING LARGE (P31 S73; `main/SaveLoadRoutine` + `func_8002B0B4`, byte-verified) L34215 --- @@ -3908,8 +3908,8 @@ Notes routinely quote that as a section id. This table resolves it. Grep bait: ` | L33935 | §427 | ★★ — A HASH IS A CORRECTNESS ORACLE WITH ZERO DIAGNOSTIC CONTENT; PRESERVE THE RED ARTIFAC | | L33954 | §428 | ★★★ — A ZERO-BYTE CROSS-JUMP BARRIER: ADVANCE THE POINTER INSIDE EACH SWITCH ARM (P31 S72; | | L33992 | §428a | ★★★ — TWO RESIDUALS THAT MOVE IN OPPOSITE DIRECTIONS UNDER EVERY LEVER USUALLY SHARE ONE C | -| L34027 | §430 | ★★★ — A SHARED TAIL IS A LATE CROSS-JUMP MERGE, NOT A SOURCE `goto` — AND SPELLING IT AS O | -| L34065 | §431 | ★★★ — SPLITTING A 27,000-LINE TU AT ITS ORIGINAL BOUNDARIES: THE JTBL SPANS TELL YOU WHERE | -| L34128 | §433 | ★★★ — ON A SWITCH FUNCTION, CASE SOURCE ORDER IS THE DOMINANT RESIDUAL — AND `match_one` I | -| L34160 | §432 | ★★★ — DEFEAT cse's MERGE OF TWO IDENTICAL MASKS BY SPELLING ONE AS A SHIFT PAIR (P31 S72/S | -| L34202 | §434 | ★★★ — TWO SYMBOLS, ONE FRAME: RUN THE FRAME CHECK BEFORE DRAFTING ANYTHING LARGE (P31 S73; | +| L34040 | §430 | ★★★ — A SHARED TAIL IS A LATE CROSS-JUMP MERGE, NOT A SOURCE `goto` — AND SPELLING IT AS O | +| L34078 | §431 | ★★★ — SPLITTING A 27,000-LINE TU AT ITS ORIGINAL BOUNDARIES: THE JTBL SPANS TELL YOU WHERE | +| L34141 | §433 | ★★★ — ON A SWITCH FUNCTION, CASE SOURCE ORDER IS THE DOMINANT RESIDUAL — AND `match_one` I | +| L34173 | §432 | ★★★ — DEFEAT cse's MERGE OF TWO IDENTICAL MASKS BY SPELLING ONE AS A SHIFT PAIR (P31 S72/S | +| L34215 | §434 | ★★★ — TWO SYMBOLS, ONE FRAME: RUN THE FRAME CHECK BEFORE DRAFTING ANYTHING LARGE (P31 S73; | diff --git a/docs/matching-cookbook.md b/docs/matching-cookbook.md index 9463de654..1f9556c4e 100644 --- a/docs/matching-cookbook.md +++ b/docs/matching-cookbook.md @@ -34021,6 +34021,19 @@ results, `jal` return values, anything with a fixed ABI register. A repeated `re switch arms is the commonest source-level way to pin `$v0` many times over, and folding them to one shared tail is free. +**SHARPENED S73 — it is not just a diagnosis, it is a PER-ARM DIAL.** `main/StreamLoadStateMachine` +(MATCH 459/459) settled the general form: **`break` vs `return 0` is a REGALLOC control you set arm +by arm.** `return 0` keeps the hard-`$v0` set live inside that arm, which EXCLUDES `$v0` from the +allocator's choices there; `break` to a shared post-switch `return 0` removes it and frees the +register. On that function case 11 needs `return 0` and every other zero-returning arm needs +`break` — one dial, eleven positions, and the correct setting is per-arm rather than global. + +So the ladder is: §3-B (fold returns to a shared tail) is the DEFAULT because it frees the register; +this section is why (the freed resource resolves coupled residuals); and the dial above is how you +put the pin BACK where a single arm needs it. `main/func_80035C4C` is the same pattern from the other +side — case 3 must `break` while case 4 keeps its explicit `return 0`, and that one hard set is what +blocks the cross-jump over-merge. + **Verification (§405-A):** all 3 jump tables and 20 relocs byte-verified past `match_one`'s masking before the MATCH was reported.