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⚡ Bolt: Optimize TryValidateRange bounds checks in VirtualMemory - #85

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bolt-optimize-try-validate-range-12743101098506108212
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⚡ Bolt: Optimize TryValidateRange bounds checks in VirtualMemory#85
manupawickramasinghe wants to merge 1 commit into
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bolt-optimize-try-validate-range-12743101098506108212

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💡 What

Optimized the TryValidateRange loop by replacing the explicit while(true) iteration with a tighter for loop over the memory regions span. This eliminates Math.Min calls, redundant remaining == 0 branching, and per-iteration ulong to int casts.

🎯 Subsystem & Bottleneck

  • Subsystem: Guest MMU & Memory Subsystem (16 KB Pages / Unified Memory)
  • Target File(s): src/SharpEmu.Core/Memory/VirtualMemory.cs
  • Bottleneck Addressed: CPU instruction overhead and missing JIT bounds-check elision in the high-frequency guest-to-host address translation hot path.

📜 Git & Contributor Context

  • Recent File History: Modified 3 days ago by @MNWickramasinghe; this optimization supplements the prior CollectionsMarshal.AsSpan refactoring and strictly isolates changes to the validation loop.
  • Conflict Check: Verified change does not overlap with recent commits or reverted attempts.

📊 Measured Performance Impact

  • Allocation Delta: Maintained 0 B/call allocation overhead.
  • Computational Impact: Elided per-iteration Math.Min calculations and reduced branches by removing the while(true) bounds validation step, enabling standard array/span JIT bounds-check elision via standard for loop indexing.

🔬 Verification Checklist

  • Executed dotnet test (All tests passed)
  • Verified zero unexpected allocations in hot path
  • Verified formatting with dotnet format
  • Confirmed thread safety and emulation accuracy

PR created automatically by Jules for task 12743101098506108212 started by @manupawickramasinghe

- Converts the `while(true)` loop to a `for` loop to allow the JIT compiler to elide bounds checks.
- Eliminates `Math.Min` and redundant branch checks.
- Removes unnecessary `ulong` to `int` casting.

Co-authored-by: manupawickramasinghe <73810867+manupawickramasinghe@users.noreply.github.com>
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Copilot AI lite review requested due to automatic review settings September 12, 2026 19:36

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2 participants