chore: add migration/ bundle for cross-machine setup
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:
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migration/project-root/ppc-manual/vmx/vmsummbm.md
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# `vmsummbm` — Vector Multiply-Sum Mixed-Sign Byte Modulo
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> **Category:** [VMX (Altivec)](../categories/vmx.md) · **Form:** [VA](../forms/VA.md) · **Opcode:** `0x10000025`
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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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| `vmsummbm` | `vmsummbm` | — | Vector Multiply-Sum Mixed-Sign Byte Modulo |
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## Syntax
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```asm
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vmsummbm [VD], [VA], [VB], [VC]
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```
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## Encoding
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### `vmsummbm` — form `VA`
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- **Opcode word:** `0x10000025`
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- **Primary opcode (bits 0–5):** `4`
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- **Extended opcode:** `37`
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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 (4) |
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| 6–10 | `VRT` | destination vector register |
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| 11–15 | `VRA` | source A |
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| 16–20 | `VRB` | source B |
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| 21–25 | `VRC` | source C / shift |
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| 26–31 | `XO` | extended opcode (6 bits) |
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## Operands
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| Field | Role | Description |
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| --- | --- | --- |
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| `VA` | vmsummbm: read | Source A vector register. |
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| `VB` | vmsummbm: read | Source B vector register. |
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| `VC` | vmsummbm: read | Source C vector register / 3-bit selector. |
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| `VD` | vmsummbm: write | Destination vector register. |
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## Register Effects
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### `vmsummbm`
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- **Reads (always):** `VA`, `VB`, `VC`
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- **Reads (conditional):** _none_
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- **Writes (always):** `VD`
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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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; Pseudocode derives directly from the xenia-rs interpreter
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; arm (see Implementation References). Operation semantics:
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; - Read source operands from the fields listed under Operands.
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; - Apply the arithmetic / logical / memory action described
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; in the Description field above.
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; - Write results to the destination register(s); update any
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; status bits enumerated under Status-Register Effects.
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; Consult the IBM AIX reference link under IBM Reference for
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; canonical PPC-style pseudocode where xenia's expression is
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; terse.
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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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**`vmsummbm`**
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- xenia-canary XML: [`tools/ppc-instructions.xml` — search for `mnem="vmsummbm"`](../../xenia-canary/tools/ppc-instructions.xml)
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- xenia-canary emit: [`src/xenia/cpu/ppc/ppc_emit_altivec.cc:1037`](../../xenia-canary/src/xenia/cpu/ppc/ppc_emit_altivec.cc#L1037)
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- xenia-rs opcode: [`crates/xenia-cpu/src/opcode.rs:107`](../../xenia-rs/crates/xenia-cpu/src/opcode.rs#L107)
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- xenia-rs decoder: [`crates/xenia-cpu/src/decoder.rs:580`](../../xenia-rs/crates/xenia-cpu/src/decoder.rs#L580)
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- xenia-rs interpreter: [`crates/xenia-cpu/src/interpreter.rs:3579-3594`](../../xenia-rs/crates/xenia-cpu/src/interpreter.rs#L3579-L3594)
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<details><summary>xenia-rs interpreter body (frozen snapshot)</summary>
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```rust
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PpcOpcode::vmsummbm => {
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// signed bytes × unsigned bytes, signed accumulator
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let a = crate::vmx::as_i8x16(ctx.vr[instr.ra()]);
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let b = ctx.vr[instr.rb()].as_bytes();
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let c = crate::vmx::as_i32x4(ctx.vr[instr.rc()]);
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let mut r = [0i32; 4];
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for i in 0..4 {
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let mut s = c[i];
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for j in 0..4 {
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s = s.wrapping_add(a[4*i+j] as i32 * b[4*i+j] as i32);
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}
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r[i] = s;
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}
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ctx.vr[instr.rd()] = crate::vmx::from_i32x4(r);
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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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- **Mixed signed×unsigned multiply-sum, modulo.** The "m" / "b" / "m" of `vmsummbm` decode as: `m`=mixed (signed `VA` × unsigned `VB`), `b`=byte lanes, `m`=modulo accumulator. Per word lane:
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```
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VD[i] = (VC[i] + Σ_{j=0..3} int8(VA[4*i + j]) * uint8(VB[4*i + j])) mod 2^32
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```
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Four signed-byte × unsigned-byte products are summed with a signed-word accumulator from `VC`, into a single signed word.
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- **Mixed signedness is unique to this instruction** — it's the canonical "signed pixel weight × unsigned pixel value" combo for filter convolution.
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- **No `VSCR[SAT]` change.** Modulo wrap; the saturating sibling for byte lanes does not exist (Altivec only provides a saturating `vmsum` for half-word widths).
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- **Big-endian byte lanes.** Lane 0 is the most-significant byte; the four contributing bytes for output word `i` are bytes `4*i .. 4*i+3`.
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- **No XER, no exceptions.**
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- **Aliasing legal.**
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- **No VMX128 sibling.**
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- **Common usage.** Per-tile signed-weight pixel sums; H.264-style 4-tap signed filter on byte data.
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## Related Instructions
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- [`vmsumubm`](vmsumubm.md) — same shape, both sources unsigned (no signed weights).
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- [`vmsumshm`](vmsumshm.md) / [`vmsumshs`](vmsumshs.md) — half-word × half-word multiply-sum (modulo / saturate).
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- [`vmsumuhm`](vmsumuhm.md) / [`vmsumuhs`](vmsumuhs.md) — unsigned half-word multiply-sum.
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- [`vmladduhm`](vmladduhm.md) — per-lane multiply-add at half width (no horizontal reduction).
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- [`vsumsws`](vsumsws.md), [`vsum4sbs`](vsum4sbs.md) — pure horizontal sums.
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## IBM Reference
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- [AIX 7.3 — `vmsummbm` (Vector Multiply-Sum Mixed-Sign Byte Modulo)](https://www.ibm.com/docs/en/aix/7.3.0?topic=set-vmsummbm-vector-multiply-sum-mixed-sign-byte-modulo-instruction)
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- [IBM AltiVec Technology Programmer's Interface Manual, Chapter 6 — Multiply-Sum Family](https://www.nxp.com/docs/en/reference-manual/ALTIVECPIM.pdf)
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