DON Chess Engine

[erashid]

DON is a modern chess engine focused on search quality, deterministic behavior, and low-level performance engineering. It implements a highly optimized alpha–beta framework with advanced pruning, selective extensions, and carefully tuned move ordering to maximize node efficiency under strict time constraints.

The engine is written in modern C++ with heavy attention to data locality, branch predictability, and instruction-level parallelism. Core subsystems make extensive use of bitboards, compact lookup tables, and cache-aware layouts, while critical hot paths are designed to minimize allocations and unpredictable control flow. DON is built to scale across contemporary x86-64 CPUs, leveraging optional SIMD and BMI instructions where available.

Time management, PV handling, and evaluation integration are engineered to behave robustly in real tournament conditions, prioritizing stability, reproducibility, and measurable Elo gains over heuristic complexity. The project serves both as a competitive engine and as a platform for experimenting with search optimizations and evaluation refinements.

DON engine now supports up to 7-man Syzygy tablebases. It allows fast and precise endgame evaluation by leveraging precomputed perfect-play databases, enabling accurate move decisions even in complex seven(7)-piece endgames.

Feature:
- Faster tablebases algorithm implemented.


Thanks
Ehsan Rashid

[erashid]

DON engine now supports up to 7-man Syzygy tablebases. It allows fast and precise endgame evaluation by leveraging precomputed perfect-play databases, enabling accurate move decisions even in complex seven(7)-piece endgames.

Feature:
- Supports up to 7-man Syzygy tablebases.
- Faster tablebases algorithm implemented.
- Faster Memory management on Linux, Ubuntu & Windows. (still working on Andriod)

Please check out the latest build of DON here:
I uploaded to 3 servers.

1. mediafire
https://www.mediafire.com/folder/06ewg9vo8mfuj/DON

2. mega
https://mega.nz/folder/Cc1zkbAR#bnycmCX38aGjK6YavnMWqw

3. pixeldrain
https://pixeldrain.com/l/cvMpTsdy

I uploaded the following builds:

Windows:
1. DON-windows-armv8
2. DON-windows-armv8-dotprod
3. DON-windows-x86-64-ssse3
4. DON-windows-x86-64-ssse3-popcnt
5. DON-windows-x86-64-sse41-popcnt
6. DON-windows-x86-64-avx2
7-. DON-windows-x86-64-bmi2
7*. DON-windows-x86-64-bmi2-comp
8-. DON-windows-x86-64-avxvnni
8*. DON-windows-x86-64-avxvnni-comp
9-. DON-windows-x86-64-avx512
9*. DON-windows-x86-64-avx512-comp

Ubuntu:
1. DON-ubuntu-x86-64-sse41-popcnt
2. DON-ubuntu-x86-64-avx2
3. DON-ubuntu-x86-64-bmi2
4. DON-ubuntu-x86-64-avxvnni

macOS:
1. DON-macos-m1-apple-silicon
2. DON-macos-x86-64-sse41-popcnt
3. DON-macos-x86-64-avx2
4. DON-macos-x86-64-bmi2

Andriod:
1. DON-android-armv8
2. DON-android-armv8-dotprod

*NOTE: *comp = Compressed version

Thanks
Ehsan Rashid

[Chacal X]

Hello.
I've said this several times, this program can't finish the game (checkmate). After playing 5 or 6 games, it freezes, making it difficult to even switch engines. Has no one else tested this? Or have they never played more than 5 games in a row with it? I really don't understand why they haven't fixed this serious flaw yet, it's regrettable...

[Joerg Oster]

DON engine now supports up to 7-man Syzygy tablebases. It allows fast and precise endgame evaluation by leveraging precomputed perfect-play databases, enabling accurate move decisions even in complex seven(7)-piece endgames.

Feature:
- Supports up to 7-man Syzygy tablebases.
- Faster tablebases algorithm implemented.
- Faster Memory management on Linux, Ubuntu & Windows. (still working on Andriod)

Please check out the latest build of DON here:
I uploaded to 3 servers.

1. mediafire
https://www.mediafire.com/folder/06ewg9vo8mfuj/DON

2. mega
https://mega.nz/folder/Cc1zkbAR#bnycmCX38aGjK6YavnMWqw

3. pixeldrain
https://pixeldrain.com/l/cvMpTsdy

I uploaded the following builds:

Windows:
1. DON-windows-armv8
2. DON-windows-armv8-dotprod
3. DON-windows-x86-64-ssse3
4. DON-windows-x86-64-ssse3-popcnt
5. DON-windows-x86-64-sse41-popcnt
6. DON-windows-x86-64-avx2
7-. DON-windows-x86-64-bmi2
7*. DON-windows-x86-64-bmi2-comp
8-. DON-windows-x86-64-avxvnni
8*. DON-windows-x86-64-avxvnni-comp
9-. DON-windows-x86-64-avx512
9*. DON-windows-x86-64-avx512-comp

Ubuntu:
1. DON-ubuntu-x86-64-sse41-popcnt
2. DON-ubuntu-x86-64-avx2
3. DON-ubuntu-x86-64-bmi2
4. DON-ubuntu-x86-64-avxvnni

macOS:
1. DON-macos-m1-apple-silicon
2. DON-macos-x86-64-sse41-popcnt
3. DON-macos-x86-64-avx2
4. DON-macos-x86-64-bmi2

Andriod:
1. DON-android-armv8
2. DON-android-armv8-dotprod

*NOTE: *comp = Compressed version

Thanks
Ehsan Rashid

Please, either include the sources or give a link to them.
DON is still based on Stockfish. Removing all references to its origin is ... well, a bit unfortunate, to say the least.
You really should comply to the license.

[erashid]

Please check out the latest build of DON here:
I uploaded to 3 servers.

1. mediafire
https://www.mediafire.com/folder/06ewg9vo8mfuj/DON

2. mega
https://mega.nz/folder/Cc1zkbAR#bnycmCX38aGjK6YavnMWqw

3. pixeldrain
https://pixeldrain.com/l/cvMpTsdy

I uploaded the following builds:

Windows:
1. DON-windows-armv8
2. DON-windows-armv8-dotprod
3. DON-windows-x86-64-ssse3
4. DON-windows-x86-64-ssse3-popcnt
5. DON-windows-x86-64-sse41-popcnt
6. DON-windows-x86-64-avx2
7-. DON-windows-x86-64-bmi2
7*. DON-windows-x86-64-bmi2-comp
8-. DON-windows-x86-64-avxvnni
8*. DON-windows-x86-64-avxvnni-comp
9-. DON-windows-x86-64-avx512
9*. DON-windows-x86-64-avx512-comp

Ubuntu:
1. DON-ubuntu-x86-64-sse41-popcnt
2. DON-ubuntu-x86-64-avx2
3. DON-ubuntu-x86-64-bmi2
4. DON-ubuntu-x86-64-avxvnni

macOS:
1. DON-macos-m1-apple-silicon
2. DON-macos-x86-64-sse41-popcnt
3. DON-macos-x86-64-avx2
4. DON-macos-x86-64-bmi2

Andriod:
1. DON-android-armv8
2. DON-android-armv8-dotprod

*NOTE: *comp = Compressed version

Thanks
Ehsan Rashid

[Chacal X]

Hi,
You posted a new version, but did you fix the bug that caused the game to freeze when you're about to win, or is it still the same?

[erashid]

Hi,
You posted a new version, but did you fix the bug that caused the game to freeze when you're about to win, or is it still the same?

Now it is fixed.

Please check out the latest build of DON here:
I uploaded to 3 servers.

Moderation: Again without updated source code. Link removed.

I uploaded the following builds:

Windows:
1. DON-windows-armv8
2. DON-windows-armv8-dotprod
3. DON-windows-x86-64-ssse3
4. DON-windows-x86-64-ssse3-popcnt
5. DON-windows-x86-64-sse41-popcnt
6. DON-windows-x86-64-avx2
7-. DON-windows-x86-64-bmi2
7*. DON-windows-x86-64-bmi2-comp
8-. DON-windows-x86-64-avxvnni
8*. DON-windows-x86-64-avxvnni-comp
9-. DON-windows-x86-64-avx512
9*. DON-windows-x86-64-avx512-comp

Ubuntu:
1. DON-ubuntu-x86-64-sse41-popcnt
2. DON-ubuntu-x86-64-avx2
3. DON-ubuntu-x86-64-bmi2
4. DON-ubuntu-x86-64-avxvnni

macOS:
1. DON-macos-m1-apple-silicon
2. DON-macos-x86-64-sse41-popcnt
3. DON-macos-x86-64-avx2
4. DON-macos-x86-64-bmi2

Andriod:
1. DON-android-armv8
2. DON-android-armv8-dotprod

*NOTE: *comp = Compressed version

Thanks
Ehsan Rashid

[Ras]

Moderation: Source code not updated again. And still spamming every day. While already having a warning for that. One month pause.

[Chacal X]

With SSE41 it crashed on the third attempt... now I'm going to test with SSE3, but I doubt you've fixed it. In fact, I think it's a very serious mistake not to test the program before releasing it on the web...

[Chacal X]

In SSE3 it played 5 games, then crashed, I'm not wasting any more time with that program.