e6d43a23ac
Bundles state that lives OUTSIDE the xenia-rs repo so a fresh clone on
another machine can be brought up to identical configuration via
migration/setup.sh:
- claude-memory/ ~/.claude/projects/-home-fabi-RE-Project-Sylpheed/memory/
(103 files, 1.1 MB - MEMORY.md + every
project_xenia_rs_*.md from audits
addis_signext through audit-058)
- project-root/dot-claude/ <project-root>/.claude/settings.json
(Stop hook + permissions)
- project-root/ppc-manual/ <project-root>/ppc-manual/
(PowerPC reference docs, 397 files, 3.7 MB)
- project-root/run-canary.sh <project-root>/run-canary.sh
- README.md Human-readable setup checklist
- setup.sh Idempotent installer (also reclones
xenia-canary at pinned HEAD 6de80dffe)
- MANIFEST.md Per-file mapping + per-file-not-bundled
restoration recipe
Excluded from bundle (not shippable via git):
- Sylpheed ISO (7.8 GB; copyright; manual copy required)
- sylpheed.db (395 MB; regenerable from XEX via analysis tooling)
- target/ build artifacts (rebuild on target)
- audit-runs probe firehoses (.log/.stdout/.stderr ~11 GB; rerun if needed)
- audit-runs memory dumps (.bin ~4.5 GB; rerun audit-026/027/029 if needed)
- xenia-canary checkout (setup.sh reclones from
git.mc02.dev/fabi/Xenia-Canary.git at HEAD 6de80dffe)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
112 lines
4.3 KiB
Markdown
112 lines
4.3 KiB
Markdown
# `isync` — Instruction Synchronize
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> **Category:** [Integer ALU](../categories/alu.md) · **Form:** [XL](../forms/XL.md) · **Opcode:** `0x4c00012c`
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<!-- GENERATED: BEGIN -->
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## Assembler Mnemonics
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| Mnemonic | XML entry | Flags | Description |
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| --- | --- | --- | --- |
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| `isync` | `isync` | — | Instruction Synchronize |
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## Syntax
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```asm
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isync
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```
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## Encoding
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### `isync` — form `XL`
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- **Opcode word:** `0x4c00012c`
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- **Primary opcode (bits 0–5):** `19`
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- **Extended opcode:** `150`
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- **Synchronising:** no
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| Bits | Field | Meaning |
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| --- | --- | --- |
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| 0–5 | `OPCD` | primary opcode (19) |
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| 6–10 | `BT/BO` | target / branch options |
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| 11–15 | `BA/BI` | source A / CR bit to test |
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| 16–20 | `BB` | source B |
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| 21–30 | `XO` | extended opcode (10 bits) |
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| 31 | `LK` | link flag |
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## Operands
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| Field | Role | Description |
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| --- | --- | --- |
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## Register Effects
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### `isync`
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- **Reads (always):** _none_
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- **Reads (conditional):** _none_
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- **Writes (always):** _none_
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- **Writes (conditional):** _none_
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## Status-Register Effects
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_No condition-register or status-register effects._
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## Operation (pseudocode)
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```
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instruction-stream synchronisation — discards speculative state.
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```
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## C Translation Example
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```c
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/* C translation: the xenia-rs interpreter arm below in */
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/* Implementation References is the authoritative semantic */
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/* snapshot. Translate it line-by-line: */
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/* - ctx.gpr[N] -> r[N] (or f[]/v[] for FPRs/VRs) */
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/* - mem.read_u*/write_u* -> mem_read_u*_be / mem_write_u*_be */
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/* - ctx.update_cr_signed(fld, v) -> update_cr_signed(fld, v) */
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/* - ctx.xer_ca / xer_ov / xer_so -> xer.CA / xer.OV / xer.SO */
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/* The Register Effects and Status-Register Effects tables above */
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/* enumerate every side effect a faithful translation must emit. */
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```
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## Implementation References
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**`isync`**
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- xenia-canary XML: [`tools/ppc-instructions.xml` — search for `mnem="isync"`](../../xenia-canary/tools/ppc-instructions.xml)
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- xenia-canary emit: [`src/xenia/cpu/ppc/ppc_emit_memory.cc:759`](../../xenia-canary/src/xenia/cpu/ppc/ppc_emit_memory.cc#L759)
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- xenia-rs opcode: [`crates/xenia-cpu/src/opcode.rs:32`](../../xenia-rs/crates/xenia-cpu/src/opcode.rs#L32)
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- xenia-rs decoder: [`crates/xenia-cpu/src/decoder.rs:714`](../../xenia-rs/crates/xenia-cpu/src/decoder.rs#L714)
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- xenia-rs interpreter: [`crates/xenia-cpu/src/interpreter.rs:1691-1693`](../../xenia-rs/crates/xenia-cpu/src/interpreter.rs#L1691-L1693)
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<details><summary>xenia-rs interpreter body (frozen snapshot)</summary>
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```rust
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PpcOpcode::sync | PpcOpcode::eieio | PpcOpcode::isync => {
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ctx.pc += 4;
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}
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```
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</details>
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<!-- GENERATED: END -->
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## Special Cases & Edge Conditions
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- **Instruction-fetch barrier.** Discards any speculatively fetched/decoded instructions and forces all subsequent ones to be re-fetched after preceding instructions complete. Required after self-modifying code, JIT-emitted code, and after MMU/page-table changes.
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- **Stronger than [`sync`](sync.md) for instruction stream**, weaker for memory stream — `isync` does not order stores against later loads. It only forces a fetch refresh.
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- **Common idiom: `dcbf` / `icbi` / `sync` / `isync`** — flush data cache, invalidate instruction cache, drain memory, refetch — used by JITs and self-modifying loaders.
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- **No operands.** Encoded as a fixed-form `XL` instruction; assemblers always emit `0x4c00012c`.
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- **Xenia-rs is a no-op.** [`interpreter.rs:1267`](../../xenia-rs/crates/xenia-cpu/src/interpreter.rs#L1267) handles `sync`/`eieio`/`isync` together. Because xenia interprets in straight-line program order without any speculative instruction cache, no barrier behaviour is needed for correctness.
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- **Privilege level: user.** Unlike most cache management ops, `isync` is unprivileged and frequently appears in userland trampolines.
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## Related Instructions
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- [`sync`](sync.md) — heavy memory barrier.
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- [`eieio`](eieio.md) — I/O ordering for caching-inhibited storage.
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- `icbi`, `dcbf`, `dcbst` — cache management ops (outside this page set) usually paired with `isync`.
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## IBM Reference
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- [AIX 7.3 — `isync` (Instruction Synchronize)](https://www.ibm.com/docs/en/aix/7.3.0?topic=set-isync-instruction-synchronize-instruction)
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