lowRISC / lowRISC/ibex

Implement time CSR

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Component:Doc Component:RTL Type:Enhancement
Dominant language
SystemVerilog
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Avg merge
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Merged PRs (30d)
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Description

We have `mtime` implemented. When implementing U mode (#88) we also need to implement `time`.

To simplify the implementation we can implement it via software trap handler, and document how such a trap handler should look like.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by examining the existing `mtime` implementation and the U-mode work referenced in #88. Then trace how a software trap handler would provide the `time` CSR behavior. Done means the CSR is implemented through that trap path and the expected trap-handler structure is documented.

Written by the indexing model from the issue text.

Assessment

Domain
embedded-iot
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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