anematodeandJoost VandeVondele
dc1686345c
Passed STC https://tests.stockfishchess.org/tests/view/69f44c1e1e5788938e86aa2a LLR: 2.93 (-2.94,2.94) <0.00,2.00> Total: 27680 W: 7340 L: 7053 D: 13287 Ptnml(0-2): 72, 2862, 7683, 3153, 70 x86 is unaffected Data from Joost's machine (Neoverse V2): ``` ==== master ==== ==== Bench: 2723949 ==== 1 Nodes/second : 276819933 2 Nodes/second : 273971948 3 Nodes/second : 275567995 Average (over 3): 275453292 ==== 5b54755db23a3de29407b805b85e7bbdef28df49 ==== ==== Bench: 2723949 ==== 1 Nodes/second : 282861542 2 Nodes/second : 279085277 3 Nodes/second : 279612223 Average (over 3): 280519680 (+1.8%) ``` Data from my M1 macbook ``` Result of 100 runs ================== base (./stockfish ) = 1474702 +/- 6169 test (...fish.rbit-pr) = 1500236 +/- 6690 diff = +25533 +/- 4011 speedup = +0.0173 P(speedup > 0) = 1.0000 ``` Hyperbola quintessence works nicely on ARM because it has an efficient bit reversal instruction `rbit`. This lets us avoid the large magic bitboards lookup table. Codegen looks nice (this is for rook attacks I think): ``` 0000000100001ecc <__ZN9Stockfish10attacks_bbILNS_9PieceTypeE3EEEyNS_6SquareEy>: 100001ecc: 2a0003e8 mov w8, w0 100001ed0: f002cb09 adrp x9, 0x105964000 <dyld_stub_binder+0x105964000> 100001ed4: 91200129 add x9, x9, #0x800 100001ed8: 8b081928 add x8, x9, x8, lsl #6 100001edc: a9402909 ldp x9, x10, [x8] 100001ee0: 8a01012b and x11, x9, x1 100001ee4: dac0016c rbit x12, x11 100001ee8: a941210d ldp x13, x8, [x8, #0x10] 100001eec: cb08018c sub x12, x12, x8 100001ef0: dac0018c rbit x12, x12 100001ef4: cb0d016b sub x11, x11, x13 100001ef8: ca0b018b eor x11, x12, x11 100001efc: 8a090169 and x9, x11, x9 100001f00: 8a01014b and x11, x10, x1 100001f04: dac0016c rbit x12, x11 100001f08: cb080188 sub x8, x12, x8 100001f0c: dac00108 rbit x8, x8 100001f10: cb0d016b sub x11, x11, x13 100001f14: ca0b0108 eor x8, x8, x11 100001f18: 8a0a0108 and x8, x8, x10 100001f1c: 8b090100 add x0, x8, x9 100001f20: d65f03c0 ret ``` closes https://github.com/official-stockfish/Stockfish/pull/6795 No functional change
Stockfish
A free and strong UCI chess engine.
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Overview
Stockfish is a free and strong UCI chess engine derived from Glaurung 2.1 that analyzes chess positions and computes the optimal moves.
Stockfish does not include a graphical user interface (GUI) that is required to display a chessboard and to make it easy to input moves. These GUIs are developed independently from Stockfish and are available online. Read the documentation for your GUI of choice for information about how to use Stockfish with it.
See also the Stockfish documentation for further usage help.
Files
This distribution of Stockfish consists of the following files:
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README.md, the file you are currently reading.
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Copying.txt, a text file containing the GNU General Public License version 3.
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AUTHORS, a text file with the list of authors for the project.
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src, a subdirectory containing the full source code, including a Makefile that can be used to compile Stockfish on Unix-like systems.
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a file with the .nnue extension, storing the neural network for the NNUE evaluation. Binary distributions will have this file embedded.
Contributing
See Contributing Guide.
Donating hardware
Improving Stockfish requires a massive amount of testing. You can donate your hardware resources by installing the Fishtest Worker and viewing the current tests on Fishtest.
Improving the code
In the chessprogramming wiki, many techniques used in Stockfish are explained with a lot of background information. The section on Stockfish describes many features and techniques used by Stockfish. However, it is generic rather than focused on Stockfish's precise implementation.
The engine testing is done on Fishtest. If you want to help improve Stockfish, please read this guideline first, where the basics of Stockfish development are explained.
Discussions about Stockfish take place these days mainly in the Stockfish Discord server. This is also the best place to ask questions about the codebase and how to improve it.
Compiling Stockfish
Stockfish has support for 32 or 64-bit CPUs, certain hardware instructions, big-endian machines such as Power PC, and other platforms.
On Unix-like systems, it should be easy to compile Stockfish directly from the
source code with the included Makefile in the folder src. In general, it is
recommended to run make help to see a list of make targets with corresponding
descriptions. An example suitable for most Intel and AMD chips:
cd src
make -j profile-build
Detailed compilation instructions for all platforms can be found in our documentation. Our wiki also has information about the UCI commands supported by Stockfish.
Terms of use
Stockfish is free and distributed under the GNU General Public License version 3 (GPL v3). Essentially, this means you are free to do almost exactly what you want with the program, including distributing it among your friends, making it available for download from your website, selling it (either by itself or as part of some bigger software package), or using it as the starting point for a software project of your own.
The only real limitation is that whenever you distribute Stockfish in some way, you MUST always include the license and the full source code (or a pointer to where the source code can be found) to generate the exact binary you are distributing. If you make any changes to the source code, these changes must also be made available under GPL v3.
Acknowledgements
Stockfish uses neural networks trained on data provided by the Leela Chess Zero project, which is made available under the Open Database License (ODbL).