https://github.com/pseitz/fastcpy

fastcpy
https://github.com/pseitz/fastcpy

Last synced: 14 days ago
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fastcpy

• Host: GitHub
• URL: https://github.com/pseitz/fastcpy
• Owner: PSeitz
• License: mit
• Created: 2023-05-23T05:58:12.000Z (about 3 years ago)
• Default Branch: main
• Last Pushed: 2023-05-24T03:48:18.000Z (about 3 years ago)
• Last Synced: 2025-03-20T04:44:46.486Z (about 1 year ago)
• Language: Rust
• Size: 3.91 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          

# FastCpy

The Rust Compiler calls `memcpy` for slices of unknown length. There's considerable overhead for that in some cases.

If you know most of you copy operations are not too big you can use `fastcpy` to speed up your program.

`fastcpy` provides a faster implementation of `memcpy` for slices up to 32bytes (64bytes with `avx`).

It is designed to contain not too much assembly, so the overhead is low.

As fall back the standard `memcpy` is called

## Double Copy Trick

`fastcpy` employs a double copy trick to copy slices of length 4-32bytes (64bytes with `avx`).

E.g. Slice of length 6 can be copied with two uncoditional copy operations.

```

/// [1, 2, 3, 4, 5, 6]

/// [1, 2, 3, 4]

///       [3, 4, 5, 6]

```