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>
178 lines
7.6 KiB
Markdown
178 lines
7.6 KiB
Markdown
# `stvx` — Store Vector Indexed
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> **Category:** [Memory](../categories/memory.md) · **Form:** [X](../forms/X.md) · **Opcode:** `0x7c0001ce`
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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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| `stvx` | `stvx` | — | Store Vector Indexed |
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| `stvx128` | `stvx128` | — | Store Vector Indexed 128 |
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## Syntax
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```asm
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stvx [VS], [RA0], [RB]
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stvx128 [VS], [RA0], [RB]
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```
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## Encoding
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### `stvx` — form `X`
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- **Opcode word:** `0x7c0001ce`
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- **Primary opcode (bits 0–5):** `31`
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- **Extended opcode:** `231`
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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 |
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| 6–10 | `RT/FRT/VRT` | destination |
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| 11–15 | `RA/FRA/VRA` | source A |
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| 16–20 | `RB/FRB/VRB` | source B |
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| 21–30 | `XO` | extended opcode (10 bits) |
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| 31 | `Rc` | record-form flag |
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### `stvx128` — form `VX128_1`
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- **Opcode word:** `0x100001c3`
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- **Primary opcode (bits 0–5):** `4`
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- **Extended opcode:** `451`
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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 | `VD128l` | destination low 5 bits |
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| 11–15 | `RA` | address register |
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| 16–20 | `RB` | offset register |
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| 21–27 | `XO` | extended opcode |
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| 28–29 | `VD128h` | destination high 2 bits |
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| 30–31 | `—` | reserved |
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## Operands
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| Field | Role | Description |
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| --- | --- | --- |
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| `VS` | stvx: read; stvx128: read | Source vector register (alias for VD on stores). |
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| `RA0` | stvx: read; stvx128: read | Source GPR; when the encoded register number is 0 the operand is the literal 64-bit zero, **not** `r0`. |
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| `RB` | stvx: read; stvx128: read | Source GPR. |
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## Register Effects
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### `stvx`
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- **Reads (always):** `VS`, `RA0`, `RB`
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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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### `stvx128`
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- **Reads (always):** `VS`, `RA0`, `RB`
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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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EA <- ((RA|0) + (RB)) & ~0xF ; align to 16
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MEM(EA, 16) <- byteswap(VS)
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```
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## C Translation Example
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```c
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/* stvx VS, RA, RB — 16-byte aligned store of a vector register */
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uint64_t base = (insn.RA == 0) ? 0 : r[insn.RA];
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uint32_t ea = (uint32_t)((base + r[insn.RB]) & ~(uint64_t)0xF);
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mem_write_vec128_be(ea, v[insn.VS]);
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```
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## Implementation References
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**`stvx`**
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- xenia-canary XML: [`tools/ppc-instructions.xml` — search for `mnem="stvx"`](../../xenia-canary/tools/ppc-instructions.xml)
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- xenia-canary emit: [`src/xenia/cpu/ppc/ppc_emit_altivec.cc:193`](../../xenia-canary/src/xenia/cpu/ppc/ppc_emit_altivec.cc#L193)
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- xenia-rs opcode: [`crates/xenia-cpu/src/opcode.rs:79`](../../xenia-rs/crates/xenia-cpu/src/opcode.rs#L79)
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- xenia-rs decoder: [`crates/xenia-cpu/src/decoder.rs:791`](../../xenia-rs/crates/xenia-cpu/src/decoder.rs#L791)
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- xenia-rs interpreter: [`crates/xenia-cpu/src/interpreter.rs:1849-1859`](../../xenia-rs/crates/xenia-cpu/src/interpreter.rs#L1849-L1859)
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<details><summary>xenia-rs interpreter body (frozen snapshot)</summary>
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```rust
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PpcOpcode::stvx => {
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let ea = if instr.ra() == 0 { 0u64 } else { ctx.gpr[instr.ra()] };
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let ea = (ea.wrapping_add(ctx.gpr[instr.rb()]) & !0xF) as u32;
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// PPCBUG-511: stvx was missing invalidate_for_write.
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if let Some(t) = ctx.reservation_table.as_ref().filter(|t| t.is_enabled()) {
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if t.has_active_reservers() { t.invalidate_for_write(ea); }
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}
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let bytes = ctx.vr[instr.rs()].as_bytes();
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for i in 0..16 { mem.write_u8(ea + i as u32, bytes[i]); }
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ctx.pc += 4;
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}
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```
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</details>
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**`stvx128`**
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- xenia-canary XML: [`tools/ppc-instructions.xml` — search for `mnem="stvx128"`](../../xenia-canary/tools/ppc-instructions.xml)
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- xenia-canary emit: [`src/xenia/cpu/ppc/ppc_emit_altivec.cc:196`](../../xenia-canary/src/xenia/cpu/ppc/ppc_emit_altivec.cc#L196)
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- xenia-rs opcode: [`crates/xenia-cpu/src/opcode.rs:79`](../../xenia-rs/crates/xenia-cpu/src/opcode.rs#L79)
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- xenia-rs decoder: [`crates/xenia-cpu/src/decoder.rs:417`](../../xenia-rs/crates/xenia-cpu/src/decoder.rs#L417)
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- xenia-rs interpreter: [`crates/xenia-cpu/src/interpreter.rs:1860-1870`](../../xenia-rs/crates/xenia-cpu/src/interpreter.rs#L1860-L1870)
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<details><summary>xenia-rs interpreter body (frozen snapshot)</summary>
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```rust
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PpcOpcode::stvx128 => {
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let ea = if instr.ra() == 0 { 0u64 } else { ctx.gpr[instr.ra()] };
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let ea = (ea.wrapping_add(ctx.gpr[instr.rb()]) & !0xF) as u32;
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// PPCBUG-511: stvx128 was missing invalidate_for_write.
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if let Some(t) = ctx.reservation_table.as_ref().filter(|t| t.is_enabled()) {
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if t.has_active_reservers() { t.invalidate_for_write(ea); }
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}
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let bytes = ctx.vr[instr.vs128()].as_bytes();
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for i in 0..16 { mem.write_u8(ea + i as u32, bytes[i]); }
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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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## Extended Pseudocode
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```
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EA <- ((RA|0) + (RB)) & ~0xF ; force 16-byte alignment
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MEM(EA, 16) <- byte_order_adjusted(VS) ; lane 0 at EA, lane 15 at EA+15
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```
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## Special Cases & Edge Conditions
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- **Alignment is forced, not checked.** The low four bits of the effective address are **cleared** before the store — alignment violations silently corrupt adjacent data rather than trap. This differs from scalar `stw` (no alignment enforcement) and from `stvewx` (which stores only one element and keeps the exact EA).
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- **Big-endian lane layout.** Vector lane 0 (the most-significant bytes of the 128-bit register) lives at the lowest address; lane 15 at `EA + 15`. On little-endian hosts the whole 16-byte block is byte-swapped at the memory boundary so the PowerPC-visible layout is preserved. Xenia's helper `mem_write_vec128_be` handles this.
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- **`RA0` semantics.** When `RA = 0` the base is the literal zero — just like scalar loads/stores. Combined with the alignment mask this lets `stvx VS, 0, RB` store to address `RB & ~0xF`.
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- **No update form.** Unlike scalar stores, VMX stores have no `u` variant that post-writes the base. Use [`stvxl`](stvxl.md) for the cache-hint variant (suggests "last" — the line is not expected to be reused soon).
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- **VMX128 sibling (`stvx128`).** Identical semantics; the only difference is the operand encoding. VMX128 uses a 7-bit register index split across three non-contiguous bit fields (`VS128l ‖ VS128h`) so it can address `v0..v127` instead of the 32-register Altivec space. All alignment, byte-order and `RA0` rules are the same.
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- **Read-before-write.** The 16-byte write occurs as one conceptual store; subsequent loads from the same address observe the complete new value. There's no split-transaction window visible to software.
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## Related Instructions
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- [`lvx`](lvx.md), [`lvx128`](lvx.md) — the load counterparts.
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- [`stvxl`](stvxl.md), [`stvxl128`](stvxl.md) — cache-hint "last-use" variants.
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- [`stvebx`](stvebx.md) / [`stvehx`](stvehx.md) / [`stvewx`](stvewx.md) — store single element (byte / half / word) at the exact (unaligned) address.
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- [`stvlx`](stvlx.md) / [`stvrx`](stvrx.md) — store-left / store-right for unaligned vector I/O.
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- [`dcbz`](dcbz.md) — zero a cache line; often paired with `stvx` in block-fill idioms.
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## IBM Reference
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- [AIX 7.3 — `stvx` (Store Vector Indexed)](https://www.ibm.com/docs/en/aix/7.3.0?topic=set-stvx-store-vector-indexed-instruction)
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- PowerISA Book II (Altivec / VMX). Xbox 360 VMX128 is Microsoft-documented in the XDK; xenia's `ppc-instructions.xml` captures the deltas.
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