A master ISA, subtracted down to a score

マスター ISA を、楽譜になるまで引き算する。

Open Prompt · Launch phase 2026-09 · Spin-off of FPGA Spectrum Engine

Layers: L1 pipeline · L2 Formation (this) · L4 Formation
Master pin: PTSG-CPU-Formation, 2026-09-03 revision
Licence: CC0 (Layers 1, 2, 4) · MIT (Layer 3)
Target: DE10-nano (Cyclone V)

FPGA Spectrum Engine has 10,240 oscillators and, until recently, no humane way to tell them what to do: five years ago the architect worked out that a drawbar per oscillator would run 300 metres. Wave-Packet Modulation Synthesis (WPMS) is the answer to that: oscillators are addressed in packets — runs of adjacent bins described by a dozen numbers (an initial amplitude, two ratios, a phase, its first and second differences across the packet, and their per-sample increments) — and a hardwired difference engine unfolds those numbers into 2,048 bins per sample period, one bin per clock.

Fig. 06 — A dozen integers unfold into N bins. パケット差分エンジン。
Fig. 06 — A dozen integers unfold into N bins. パケット差分エンジン。

Something has to write those dozen numbers, per packet, per sample, and switch them without a click. That something is a tiny instruction-driven timing core (PTSG-Core) wearing a data-processing “formation” (PTSG-CPU-Formation, the master ISA). PTSG-WPMS-Formation is the first subtraction profile of that master: it keeps a decision register in which every choice is keyed to a master decision — inherit, restrict, omit, extend — and adds only what the master deliberately left to its first customer.

Fig. 01 — Four repositories, one machine.
Fig. 01 — Four repositories, one machine.
Fig. 02 — Every decision keyed to a master ID, in four words.
Fig. 02 — Every decision keyed to a master ID, in four words.

What the first week of the profile produced

One Stay is one packet. The Core’s Stay counter is the difference engine’s k. Packet length is the Stay value, supplied by the formation through a two-stage register so the Core always sees a frozen number — no packet can be stretched mid-flight.

The ISA speaks integers. Every register and page slot has an integer width (16 or 32 bits). Fixed-point meaning belongs to programs: a program writes its shift register (WSH) before its first multiply-accumulate. The master’s very first program, re-run on the profile with two extra instructions in front, computes e to the same digits; without them it overflows — the ISA does not know your Q.

A 256-word register map: eight 16-word packet blocks (shadow written, active read, swapped on the trailing edge) plus an inbox that external writers use so the shadow keeps a single writer. Accepted by the WPMS side as customer. The atomic swap is designed to prevent seams from partial parameter updates.

Nothing hand-edited. The profile’s translation contract is generated from the master’s (itself generated from the master’s normative chapter) by folding the register mechanically; a validator rejects what the register removed.

Fig. 03 — 256 words, one block is one packet. 256 語アドレス空間。
Fig. 03 — 256 words, one block is one packet. 256 語アドレス空間。

Everything is Open Prompt: the specification, the reasoning traces (including the correspondence between the three AI amanuenses — master, profile, customer — each a separate session), and the reference tools. Numbers bind to DE10-nano and are measured, not promised. The exp(x) result below is a reference-tool/oracle result; DE10-nano hardware evidence is still to come.

MeasureValue
Bins per module, one bin per clock2,048
ISA-visible register map256 words
Master instructions → profile18 → 17
Upstream discrepancies fixed4/4
exp(x) maximum absolute error, oracle7.39e−09, identical to the master

JA 要旨: 10,240 オシレータに人間らしく指示する唯一の道が「パケット」——十数個の数で記述される隣接ビン群——であり、それを毎パケット・毎サンプル書き換えて無音で切り替えるのが本 Formation。最初の一週間で、Stay = パケット、整数 ISA とプログラム所有のシフト、256 語のレジスタマップ、手編集なしの契約生成鎖が成立。三つの祐筆セッション間の往復も第2層として公開。実機での検証結果は今後追加します。

Status · 現状（2026-09 launch material）

Provenance · 来歴

Architecture and all rulings: Tsuneo Ohnaka. Drafting support: Claude (Anthropic), the profile’s amanuensis; the master’s and the customer’s amanuenses are separate sessions.
アーキテクチャと全裁定: 大中庸生。起草支援: Claude (Anthropic)。

Measured, not promised. 約束ではなく計測。
Open Prompt · fourth repository of the PTSG ecosystem · CC0 / MIT