In the spirit of previous such PRs, this PR proposes a collection of nonfunctional changes.
I am happy to incorporate changes from other devs, and revert some of the proposed changes if the maintainers ask me to.
Apart from trivial changes, the proposed changes so far include:
* A requested edit to `AUTHORS` and a resorting of all entries, following DIN 5007 for the treatment of any special characters.
* Exclude the two recent integer type renaming commits from git blame.
* Tightening of some static asserts in `history.h` to avoid overflows. (Note that rounding errors for floating point types could lead to the assert in `operator<<` triggering at run-time.)
* Re-instate the 0.5s maximal thinking time in case of a single legal move and reword the comment to make it clear that it should not be tuned.
* ~~A small refactoring of the network loading code thanks to @dubslow.~~
* A refactoring of the "dtz is dtm" code, also thanks to @dubslow.
closes https://github.com/official-stockfish/Stockfish/pull/6928
No functional change
GCC 12.2 added `__rbitll` intrinsic to `arm_acle.h`, so we can add a fallback for older versions
Clang 10 (our new minimum supported version) is unaffected by all this
closes https://github.com/official-stockfish/Stockfish/pull/6949
No functional change
Passed STC non-regression on avx512icl (https://tests.stockfishchess.org/tests/view/6a421b46f97ff95f78795061)
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 81632 W: 21240 L: 21075 D: 39317
Ptnml(0-2): 184, 8907, 22464, 9082, 179
Passed STC non-regression on bmi2 (https://tests.stockfishchess.org/tests/view/6a41f6f9f97ff95f7879503e)
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 78112 W: 20411 L: 20245 D: 37456
Ptnml(0-2): 188, 8449, 21632, 8583, 204
After #6845 , pext attacks are slower or equal to parallel-hyperbola attacks which works on all architectures that pext supports. SVE2 supports pext/pdep in vector registers, but it's much slower than the `rbit`-based HQ that we have on ARM, so I don't foresee the code being useful there.
Ofc I don't think we should remove the `bmi2` build or anything, because it's nice for people to be able to freely use pext when testing ideas, and I'm sure we'll some day find another use for it!
closes https://github.com/official-stockfish/Stockfish/pull/6939
No functional change
Co-authored-by: Dubslow <bunslow@gmail.com>
example of using, to avoid mixed usage of std::uint/std::int and uint/int...
```cpp
using u64 = std::uint64_t;
using u32 = std::uint32_t;
using u16 = std::uint16_t;
using u8 = std::uint8_t;
using i64 = std::int64_t;
using i32 = std::int32_t;
using i16 = std::int16_t;
using i8 = std::int8_t;
using usize = std::size_t;
using isize = std::ptrdiff_t;
#if defined(__GNUC__) && defined(IS_64BIT)
__extension__ using u128 = unsigned __int128;
__extension__ using i128 = signed __int128;
#endif
```
closes https://github.com/official-stockfish/Stockfish/pull/6874
No functional change
Hyperbola Quintessence works out without the "... * 2" in r and rr. This then is cheap enough to compute at runtime, instead of looking it up, for a minor speedup.
Passed apple-silicon|armv8|loongarch64 STC:
https://tests.stockfishchess.org/tests/view/6a15f031818cacc1db0aca49
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 410208 W: 104369 L: 103556 D: 202283
Ptnml(0-2): 758, 43951, 114883, 44744, 768
Verified attacks_bb<ROOK>() and attacks_bb<BISHOP>() assembly remains unchanged on x86 (gcc 16.1.1).
closes https://github.com/official-stockfish/Stockfish/pull/6870
No functional change
passed STC (https://tests.stockfishchess.org/tests/view/6a1157dc818cacc1db0ac172):
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 29792 W: 7759 L: 7465 D: 14568
Ptnml(0-2): 75, 3206, 8033, 3514, 68
Also passed STC after cleanups https://tests.stockfishchess.org/tests/view/6a121beb818cacc1db0ac35e
vondele's local test:
Result of 100 runs
base (./stockfish.master ) = 1136025 +/- 2816
test (./stockfish.patch2 ) = 1171370 +/- 2848
diff = +35346 +/- 3275
speedup = +0.0311
P(speedup > 0) = 1.0000
Basically we just do hyperbola quintessence in parallel. AVX2 doesn't have efficient bit reversal so we only do it for file and bishop attacks, then do rank attacks separately with a lookup table. This LUT is much smaller which is why this seems to be faster than standard magics.
closes https://github.com/official-stockfish/Stockfish/pull/6845
No functional change
Over the past few months our attacks and bitboard logic got a bit more involved and target specific, so I think it makes sense to split this up a bit more into separate files.
While it's not in an ideal state I think it's first step and can be improved later, `pawn_attacks_bb` could also be moved into the attacks.h but this was more of an oversight from my side.
closes https://github.com/official-stockfish/Stockfish/pull/6833
No functional change
