arch-riscv: Add an assert for vector splitting.

[jueshiwenli]

Change-Id: I2aae4e4c13f0c528354d9e404bd857f42175ddb9

Summary by CodeRabbit

• Chores

  • Added an internal validation to improve reliability of vector instruction construction.

• Documentation

  • Added a Chinese design-doc index for Kunminghu vector docs.
  • Added a new design document describing control and sequencing for vector configuration instructions, including timing, risk mitigation, and verification guidance.

[github-actions]

🚀 RVV Performance test triggered: spec06int-rvv-0.8c

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 7117ee46-cc7d-4946-a53a-cb4065aee4f8

📥 Commits

Reviewing files that changed from the base of the PR and between 0729129 and 9a3d45c.

📒 Files selected for processing (2)

• docs/design-docs/vector/README.md
• docs/design-docs/vector/vector-config-decode-block-design.md

✅ Files skipped from review due to trivial changes (2)

• docs/design-docs/vector/README.md
• docs/design-docs/vector/vector-config-decode-block-design.md

---

📝 Walkthrough

Walkthrough

Added a runtime assertion in the VectorIntMacroConstructor template requiring num_microops be exactly 1 or an even number. Also added Chinese vector design documentation: an index README and a detailed design doc for vector-config decode/commit serialization behavior.

Changes

Vector Arithmetic Validation

Layer / File(s)	Summary
Template Check src/arch/riscv/isa/vector/base/vector_arith.temp.isa	Insert `assert(num_microops == 1

Vector Design Documentation (Chinese)

Layer / File(s)	Summary
Docs Index docs/design-docs/vector/README.md	Add Kunminghu Vector documentation index README with homepage link, scope statement, and link to the design doc.
Design Specification docs/design-docs/vector/vector-config-decode-block-design.md	Add detailed design doc describing decode-stage serialization for vector-config (vset*) instructions, same-cycle push truncation, commit-stage younger-executed detection with squashAfter refresh/replay, timing diagrams, risks, validation plan, and affected code references.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Suggested reviewers

• huxuan0307
• Anzooooo
• weidingliu

Poem

🐰 I nibble code by moonlight's beam,
I hop through asserts, neat and keen,
One or even—rules so sweet,
Docs bloom like clover at my feet,
Happy hops for vector dreams! 🥕✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The PR title 'arch-riscv: Add an assert for vector splitting' accurately matches the main code change, which adds a runtime assertion in the vector arithmetic template to constrain num_microops.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch xs-vector-260422

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[Copilot]

Pull request overview

Adds a debug-time invariant check in the RISC-V vector arithmetic ISA template to validate assumptions about how many micro-ops are created when vector instructions are split based on LMUL.

Changes:

• Add an assert to ensure num_microops is either 1 or an even number before generating micro-ops.

---

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[github-actions]

🚀 Coremark Smoke Test Results

Branch	IPC	Change
Base (xs-dev)	2.3051	-
This PR	2.3051	➡️ 0.0000 (0.00%)

✅ Difftest smoke test passed!

[github-actions]

🚀 Coremark Smoke Test Results

Branch	IPC	Change
Base (xs-dev)	2.3130	-
This PR	2.3130	➡️ 0.0000 (0.00%)

✅ Difftest smoke test passed!