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/vmx128/vmaddcfp128.md
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# `vmaddcfp128` — Vector128 Multiply Add Floating Point
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> **Category:** [VMX128](../categories/vmx128.md) · **Form:** [VX128](../forms/VX128.md) · **Opcode:** `0x14000110`
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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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| `vmaddcfp128` | `vmaddcfp128` | — | Vector128 Multiply Add Floating Point |
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## Syntax
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```asm
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vmaddcfp128 [VD], [VA], [VD], [VB]
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```
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## Encoding
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### `vmaddcfp128` — form `VX128`
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- **Opcode word:** `0x14000110`
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- **Primary opcode (bits 0–5):** `5`
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- **Extended opcode:** `272`
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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 or 5) |
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| 6–10 | `VD128l` | destination low 5 bits |
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| 11–15 | `VA128l` | source A low 5 bits |
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| 16–20 | `VB128l` | source B low 5 bits |
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| 21 | `VA128H` | source A high bit |
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| 22 | `—` | reserved |
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| 23–25 | `VC` | optional VC / XO sub-field |
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| 26 | `VA128h` | source A middle bit |
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| 27 | `—` | reserved |
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| 28–29 | `VD128h` | destination high 2 bits |
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| 30–31 | `VB128h` | source B high 2 bits |
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## Operands
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| Field | Role | Description |
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| --- | --- | --- |
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| `VA` | vmaddcfp128: read | Source A vector register. |
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| `VD` | vmaddcfp128: read; vmaddcfp128: write | Destination vector register. |
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| `VB` | vmaddcfp128: read | Source B vector register. |
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## Register Effects
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### `vmaddcfp128`
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- **Reads (always):** `VA`, `VD`, `VB`
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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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**`vmaddcfp128`**
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- xenia-canary XML: [`tools/ppc-instructions.xml` — search for `mnem="vmaddcfp128"`](../../xenia-canary/tools/ppc-instructions.xml)
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- xenia-canary emit: [`src/xenia/cpu/ppc/ppc_emit_altivec.cc:812`](../../xenia-canary/src/xenia/cpu/ppc/ppc_emit_altivec.cc#L812)
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- xenia-rs opcode: [`crates/xenia-cpu/src/opcode.rs:100`](../../xenia-rs/crates/xenia-cpu/src/opcode.rs#L100)
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- xenia-rs decoder: [`crates/xenia-cpu/src/decoder.rs:614`](../../xenia-rs/crates/xenia-cpu/src/decoder.rs#L614)
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- xenia-rs interpreter: [`crates/xenia-cpu/src/interpreter.rs:4492-4509`](../../xenia-rs/crates/xenia-cpu/src/interpreter.rs#L4492-L4509)
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<details><summary>xenia-rs interpreter body (frozen snapshot)</summary>
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```rust
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PpcOpcode::vmaddcfp128 => {
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// ISA: (VD) <- (VA × VD) + VB. Canary InstrEmit_vmaddcfp128 (cc:819): MulAdd(VA, VD, VB).
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// Previous code computed di.mul_add(bi, ai) = VD×VB+VA — both operands wrong
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// (PPCBUG-425). Fix: ai.mul_add(di, bi) = VA×VD+VB.
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let a = ctx.vr[instr.va128()].as_f32x4();
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let b = ctx.vr[instr.vb128()].as_f32x4();
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let d = ctx.vr[instr.vd128()].as_f32x4();
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let mut r = [0f32; 4];
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for i in 0..4 {
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let ai = vmx::flush_denorm(a[i]);
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let bi = vmx::flush_denorm(b[i]);
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let di = vmx::flush_denorm(d[i]);
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// PPCBUG-437: flush subnormal output too.
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r[i] = vmx::flush_denorm(ai.mul_add(di, bi));
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}
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ctx.vr[instr.vd128()] = xenia_types::Vec128::from_f32x4_array(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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- **Xbox-specific fused multiply-add variant.** Each lane computes `VD[i] = VD[i] * VB[i] + VA[i]` — note that `VD` is both source and destination (xenia reads `VD` first, then writes). This is *not* the standard [`vmaddfp`](../vmx/vmaddfp.md) operand order: the "addend" position is `VA`, the other factor is `VB`, and `VD` carries the on-going accumulator. The mnemonic's trailing `c` denotes "accumulator-in-VD" rather than a separate `VC` operand.
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- **Fused, single-rounding.** Xenia uses `f32::mul_add`, which maps to a host FMA instruction when available. Bit-for-bit result depends on host support; xenia-canary's LLVM path emits the equivalent IR node.
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- **IEEE-754 binary32 lanes; `VSCR[NJ]` honoured.**
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- **No VSCR[SAT], no FPSCR update.**
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- **NaN propagation** per IEEE-754.
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- **VMX128 register-fusion** (7-bit IDs on `VA`, `VB`, `VD`).
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- **No IBM AIX entry** — Xenon-only.
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- **No `Rc`, no XER.**
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## Related Instructions
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- [`vmaddfp`](../vmx/vmaddfp.md), [`vmaddfp128`](../vmx/vmaddfp.md) — standard fused `(VA × VC) + VB`.
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- [`vmulfp128`](vmulfp128.md) — plain lane-wise float multiply.
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- [`vnmsubfp`](../vmx/vnmsubfp.md) — negative-multiply-subtract.
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- [`vmsum3fp128`](vmsum3fp128.md), [`vmsum4fp128`](vmsum4fp128.md) — dot-product reductions.
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## IBM Reference
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- No IBM AIX entry — this is an Xbox 360 VMX128 extension. Its semantics differ from the base Altivec [`vmaddfp`](../vmx/vmaddfp.md) in the operand order (accumulator in `VD`, not `VC`).
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- Xbox 360 XDK, Altivec-128 (VMX128) extensions.
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- [IBM AltiVec Technology Programmer's Interface Manual, Chapter 5 — Floating-Point Arithmetic](https://www.nxp.com/docs/en/reference-manual/ALTIVECPIM.pdf) for the base FMA semantics.
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