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chore: add migration/ bundle for cross-machine setup

Browse Source 
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>
This commit is contained in:
MechaCat02
2026-05-10 21:38:38 +02:00
parent 8e709b0a24
commit e6d43a23ac
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# `vsubcuw` — Vector Subtract Carryout Unsigned Word
> **Category:** [VMX (Altivec)](../categories/vmx.md) · **Form:** [VX](../forms/VX.md) · **Opcode:** `0x10000580`
<!-- GENERATED: BEGIN -->
## Assembler Mnemonics
| Mnemonic | XML entry | Flags | Description |
| --- | --- | --- | --- |
| `vsubcuw` | `vsubcuw` | — | Vector Subtract Carryout Unsigned Word |
## Syntax
```asm
vsubcuw [VD], [VA], [VB]
```
## Encoding
### `vsubcuw` — form `VX`
- **Opcode word:** `0x10000580`
- **Primary opcode (bits 0–5):** `4`
- **Extended opcode:** `1408`
- **Synchronising:** no
| Bits | Field | Meaning |
| --- | --- | --- |
| 0–5 | `OPCD` | primary opcode (4) |
| 6–10 | `VRT/VD` | destination vector register |
| 11–15 | `VRA/VA` | source A vector register |
| 16–20 | `VRB/VB` | source B vector register |
| 21–31 | `XO` | extended opcode (11 bits) |
## Operands
| Field | Role | Description |
| --- | --- | --- |
| `VA` | vsubcuw: read | Source A vector register. |
| `VB` | vsubcuw: read | Source B vector register. |
| `VD` | vsubcuw: write | Destination vector register. |
## Register Effects
### `vsubcuw`
- **Reads (always):** `VA`, `VB`
- **Reads (conditional):** _none_
- **Writes (always):** `VD`
- **Writes (conditional):** _none_
## Status-Register Effects
_No condition-register or status-register effects._
## Operation (pseudocode)
```
; Pseudocode derives directly from the xenia-rs interpreter
; arm (see Implementation References). Operation semantics:
; - Read source operands from the fields listed under Operands.
; - Apply the arithmetic / logical / memory action described
; in the Description field above.
; - Write results to the destination register(s); update any
; status bits enumerated under Status-Register Effects.
; Consult the IBM AIX reference link under IBM Reference for
; canonical PPC-style pseudocode where xenia's expression is
; terse.
```
## C Translation Example
```c
/* C translation: the xenia-rs interpreter arm below in */
/* Implementation References is the authoritative semantic */
/* snapshot. Translate it line-by-line: */
/* - ctx.gpr[N] -> r[N] (or f[]/v[] for FPRs/VRs) */
/* - mem.read_u*/write_u* -> mem_read_u*_be / mem_write_u*_be */
/* - ctx.update_cr_signed(fld, v) -> update_cr_signed(fld, v) */
/* - ctx.xer_ca / xer_ov / xer_so -> xer.CA / xer.OV / xer.SO */
/* The Register Effects and Status-Register Effects tables above */
/* enumerate every side effect a faithful translation must emit. */
```
## Implementation References
**`vsubcuw`**
- xenia-canary XML: [`tools/ppc-instructions.xml` — search for `mnem="vsubcuw"`](../../xenia-canary/tools/ppc-instructions.xml)
- xenia-canary emit: [`src/xenia/cpu/ppc/ppc_emit_altivec.cc:1671`](../../xenia-canary/src/xenia/cpu/ppc/ppc_emit_altivec.cc#L1671)
- xenia-rs opcode: [`crates/xenia-cpu/src/opcode.rs:125`](../../xenia-rs/crates/xenia-cpu/src/opcode.rs#L125)
- xenia-rs decoder: [`crates/xenia-cpu/src/decoder.rs:536`](../../xenia-rs/crates/xenia-cpu/src/decoder.rs#L536)
- xenia-rs interpreter: [`crates/xenia-cpu/src/interpreter.rs:3391-3399`](../../xenia-rs/crates/xenia-cpu/src/interpreter.rs#L3391-L3399)
<details><summary>xenia-rs interpreter body (frozen snapshot)</summary>
```rust
PpcOpcode::vsubcuw => {
// "Subtract Carryout": r = 1 if a >= b (no borrow), 0 otherwise.
let a = ctx.vr[instr.ra()].as_u32x4();
let b = ctx.vr[instr.rb()].as_u32x4();
let mut r = [0u32; 4];
for i in 0..4 { r[i] = if a[i] >= b[i] { 1 } else { 0 }; }
ctx.vr[instr.rd()] = xenia_types::Vec128::from_u32x4_array(r);
ctx.pc += 4;
}
```
</details>
<!-- GENERATED: END -->
## Special Cases & Edge Conditions
- **"Borrow out" producer for unsigned word subtract.** Each of the 4 lanes produces `1` if `VA.w[i] >= VB.w[i]` (no borrow) and `0` otherwise. This is an **inverted** borrow — conventional borrow would be `1` on underflow, but Altivec's `vsubcuw` returns the opposite to match the `XER[CA]` convention used by scalar `subfc` / `subfe`.
- **Complements [`vadduwm`](vadduwm.md) / [`vaddcuw`](vaddcuw.md)** for 256-bit (or wider) multi-precision arithmetic. After the lane subtract, chain the 4-bit borrow vector into the next word via [`vsubeuwm`](vsubeuwm.md)-style helpers (or manual software glue, since Altivec has no direct `sube`).
- **No saturation, no flags, no VSCR effect.** Despite being in the "carry" family, `vsubcuw` doesn't touch `VSCR[SAT]`.
- **Big-endian word lanes.**
- **No VMX128 sibling.**
## Related Instructions
- [`vsubuwm`](vsubuwm.md) — the difference value (unsigned modulo).
- [`vaddcuw`](vaddcuw.md) — the paired carry-out producer for unsigned-add.
- [`vadduwm`](vadduwm.md) — unsigned word add (modulo).
## IBM Reference
- [AIX 7.3 — `vsubcuw` (Vector Subtract and Write Carry-Out Unsigned Word)](https://www.ibm.com/docs/en/aix/7.3.0?topic=set-vsubcuw-vector-subtract-write-carry-out-unsigned-word-instruction)
- [IBM AltiVec Technology Programmer's Interface Manual, Chapter 4 — Integer Arithmetic](https://www.nxp.com/docs/en/reference-manual/ALTIVECPIM.pdf)