ADR 0103: Private CUBE vector execution and CELL rearrangement

Context

Issue #151 was accepted by the architecture owner on 2026-08-25. This record keeps one coherent decision for private Local CUBE vector execution and the four CELL rearrangement operations, and establishes accepted ADR ownership for their four contract clauses and instruction subjects. Current normative meaning remains in the accepted ASL contracts and their generated projections.

Decision

The six old tile selectors are retired: TPARTADD, TPARTMUL, TPARTMAX, and TPARTMIN (0x071..0x074), TFILLPAD (0x065), and TTRANS (0x06E). Their selectors remain reserved-illegal. No alias or replacement is introduced. This retires only the corresponding decisions in ADR-0082 and ADR-0083; those ADRs are not retired wholesale. This ADR intentionally does not use metadata supersedes for that scoped retirement.

The following 34 existing element-wise instructions accept ordinary Local CUBE_M32 and Local CUBE_M16 execution:

TADD TAND TDIV TMAX TMIN TMUL TOR TREM TSHL TSHR TSUB TXOR
TABS TEXP TLOG TNEG TNOT TRECIP TRELU TRSQRT TSQRT
TADDS TANDS TDIVS TMAXS TMINS TMULS TORS TREMS
TSHLS TSHRS TSUBS TXORS TFMA

CUBE_N8, Shared layouts, mixed layouts, and the excluded TCMP, TCMPS, TSEL, TSELS, and TCVT forms remain illegal. Existing logical-coordinate element-wise contracts continue to define shape, type, valid-region, and value behavior; this decision does not introduce a new element-wise spelling.

The SFU TEPL Mode=3 selectors for CELL rearrangement are frozen as follows:

• TPERMUTE is selector 0x075, a raw two-source per-row byte lookup using a U8 index Tile.
• TSHUF is selector 0x076, a raw U32-word shuffle with UP, DOWN, BFLY, and IDX modes, SELF/ZERO selection, and M32/M16 grouping.
• TPACK is selector 0x077, U32 byte-field assembly.
• TUNPACK is selector 0x078, U32 zero-extended byte-field extraction.

Controls, operand bindings, source-definedness, valid-region and padding inspection, and fresh-destination allocation follow and agree with the accepted ASL contracts and the issue handoff. This ADR does not add alternate control encodings or operand forms.

For a decoded bundle, missing, repeated, or surplus B.IOR structure is a BundleControl fault. Invalid controls, indices, dtypes, layouts, or shapes are TileLegality faults. An unallocated selector is an IllegalInstruction. PE_MASK=0000 is a strict no-op after legal decode and does not read operands, allocate a destination, or raise a later semantic fault.

Compatibility and protected behavior

Raw CELL order is observable only for TPERMUTE, TSHUF, TPACK, and TUNPACK. Ordinary element-wise operations remain logical-coordinate based. This decision does not add reductions, replace transpose, enable GM conversion, add predicate behavior, or define numeric conversion semantics.

The selector retirement is an assembly and compatibility break: the retired encodings are rejected and have no compatibility aliases. Compiler intrinsic, emulator, and RTL adoption remain separate follow-ups to the PTO-ASL contract.

Release boundary

The change has required release impact and is selected for architecture release 0.58.5. ADR-0108 owns the compatibility and publication boundary; this ADR continues to own only the accepted architecture decision.

Verification

Focused decoded and direct AVS evidence covers the accepted vector and CELL rearrangement paths, rejection/no-effect boundaries, and the bundle fault boundary. The ordinary PR V1 gates are the applicable repository verification; release validation and V2 evidence are not claimed by this decision.