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
Fixes problems with non-ASCII characters in paths. Fixes#3424.
Changes
- Bump the minimum supported Clang version to 11 to support std::filesystem
- Use std::optional for empty values instead of string sentinels like "None"
- Remove the FixedString class
- Move the EvalFile network path from the network struct to the engine
- Simplify parts of the command-line handling
- Remove the old dual-net logic from export_net
- And ofc we now support non-ascii paths for windows
Behavior Change
- Because the EvalFile is no longer part of the network, it won't be included in the hashing, thus the network sharing is no longer dependent on the EvalFile path
- As a result, if the binary version and network are the same, changing only the EvalFile location will now reuse the same shared network
This also fixes a master bug where:
```
export_net None
setoption name EvalFile value None
export_net None
Failed to export a net
```
would fail on the second export. With this patch, the second export succeeds.
Quick Fishtest Check that nets load like normal.
https://tests.stockfishchess.org/tests/view/6a455593f97ff95f787954da
<img width="833" height="1137" alt="image" src="https://github.com/user-attachments/assets/fffee63b-c63a-4d5e-b13d-87d58bc28c88" />
closes https://github.com/official-stockfish/Stockfish/pull/6937
No functional change
Co-authored-by: anematode <timothy.herchen@gmail.com>
Performance on Spacemit K3, thanks @edolnx for testing
master:
Total time (ms) : 65200
Nodes searched : 3493826
Nodes/second : 53586
riscv-scalable-port:
Total time (ms) : 15834
Nodes searched : 3493826
Nodes/second : 220653
Also thanks to @camel-cdr for guidance on RVV programming, and https://cloud-v.co for supplying an RVV instance to test with
passed STC:
LLR: 2.81 (-2.94,2.94) <0.00,2.00>
Total: 1152 W: 527 L: 108 D: 517
Ptnml(0-2): 0, 17, 167, 348, 44
https://tests.stockfishchess.org/tests/view/6a39895b3036e45021aeb368
## Summary
We've had a `riscv64` target for a while, but haven't really optimized for it, in particular the vector extension (RVV).
RVV, like SVE, is based on a scalable vector system where the vector length ranges from 128 to 65536. In practice implementations are between 128 and 2048, and 256 bits is quite common (e.g. the Spacemit K3 system above). Unfortunately this doesn't fit well into the rest of our code which assumes a fixed vector length, so what I've done is bypass the `VECTOR` ifdef (which now basically means "FIXED_LENGTH_VECTOR") and just have RVV-specific paths.
The ability to explicitly control `vl` makes the code quite readable, in my opinion. We use LMUL>1 in most places to take advantage of multi-vector instructions. Generally the LMULs were chosen to best support a 256-bit vlen, which is very common, but by virtue of how the vlen control works, the code works with any vlen. In a couple places, i.e., `get_changed_pieces` and `AffineTransformSparseInput::propagate`, we have separate implementations depending on the vlen, because the optimal LMUL varies a lot between implementations.
One little wrinkle is that `load_as` is compiled to a sequence of byte loads, because although unaligned loads are legal in RVA23, the spec says that they *may* be extremely slow (even though they usually aren't, in actual hw), so compilers are conservative. Thus I aligned the relevant buffers and made the semantics of `load_as` that the operand is aligned, by adding a runtime assertion.
### Universal binary
Adding a universal binary is pretty easy and we can just cross-compile. There are two targets: baseline rv64gc and riscv64-rva23, which is actually a smaller subset of RVA23 that also works on some older processors that don't support the full thing. We use clang because GCC, until recently, has a nasty bug with LTO and RVV.
Like the universal ARM and x86 builds, we check all the builds in CI. In this case we run bench with multiple vlens, 128 through 1024.
In the meantime I deleted the existing broken and unused riscv64 tests.
### Follow-ups
- Optimizations
- zvdot4a8i path
closes https://github.com/official-stockfish/Stockfish/pull/6920
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>
When compiling for Android (COMP=ndk) on macOS, the build fails because the
NDK's LLVM toolchain does not recognize the macOS-specific flags
-mdynamic-no-pic and -mmacosx-version-min.
This PR wraps these flags with ifneq ($(COMP),ndk) condition to skip them
during Android cross-compilation.
Please squash and merge this PR.
closes https://github.com/official-stockfish/Stockfish/pull/6927
No functional change
This network is trained by adding the following binpacks, relabeled by @vondele and totaling 74B positions, to the distillation fine-tuning stage:
```
- vondele/from_kaggle_1_relabel/leela96-filt-v2.min.split_0.relabel-BT4-tf13tune.binpack
- vondele/from_kaggle_1_relabel/leela96-filt-v2.min.split_1.relabel-BT4-tf13tune.binpack
- vondele/from_kaggle_1_relabel/leela96-filt-v2.min.split_2.relabel-BT4-tf13tune.binpack
- vondele/from_kaggle_1_relabel/leela96-filt-v2.min.split_3.relabel-BT4-tf13tune.binpack
- vondele/from_kaggle_1_relabel/leela96-filt-v2.min.split_4.relabel-BT4-tf13tune.binpack
- vondele/from_kaggle_2_relabel/T60T70wIsRightFarseerT60T74T75T76.split_0.relabel-BT4-tf13tune.binpack
- vondele/from_kaggle_2_relabel/T60T70wIsRightFarseerT60T74T75T76.split_1.relabel-BT4-tf13tune.binpack
- vondele/from_kaggle_2_relabel/T60T70wIsRightFarseerT60T74T75T76.split_2.relabel-BT4-tf13tune.binpack
- vondele/from_kaggle_2_relabel/T60T70wIsRightFarseerT60T74T75T76.split_3.relabel-BT4-tf13tune.binpack
- vondele/from_kaggle_2_relabel/T60T70wIsRightFarseerT60T74T75T76.split_4.relabel-BT4-tf13tune.binpack
```
The relabeling effort has been completed during the testing of this patch, and a full training run is on the way. Thanks to @vondele, @anematode, @Disservin, @yl25946, and all who've contributed to the process.
Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 24512 W: 6500 L: 6201 D: 11811
Ptnml(0-2): 69, 2772, 6300, 3021, 94
https://tests.stockfishchess.org/tests/view/6a40b7083036e45021aebbd6
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 15708 W: 4232 L: 3960 D: 7516
Ptnml(0-2): 8, 1572, 4420, 1848, 6
https://tests.stockfishchess.org/tests/view/6a413d293036e45021aebc84
nettest PR: https://github.com/vondele/nettest/pull/388
closes https://github.com/official-stockfish/Stockfish/pull/6932
Bench: 2102535
Co-authored-by: Joost VandeVondele <Joost.VandeVondele@gmail.com>
Deduplicating Color-Specific Piece Validation.
The validation checks for the number of pawns and additional promoted pieces are duplicated for WHITE and BLACK. We can combine this logic into a single range-based for loop over both colors.
closes https://github.com/official-stockfish/Stockfish/pull/6922
No functional change
do_null_move copies the whole StateInfo from the previous state, which leaves capturedPiece holding the piece captured by the last real move, so inside the null-move subtree captured_piece() reports a stale capture. The priorCapture consumers in search are all guarded by prevSq != SQ_NONE or (ss-1)->currentMove.is_ok(), which are false at the null-move child, but the stalemate verification gate in qsearch reads captured_piece() unguarded and can be spuriously triggered by the stale value.
Clear the field, since a null move captures nothing.
Passed non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 82784 W: 21172 L: 21011 D: 40601
Ptnml(0-2): 194, 8976, 22923, 9073, 226
https://tests.stockfishchess.org/tests/view/6a2b5b356b4aa63ddbf31518
Passed non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 118134 W: 30007 L: 29891 D: 58236
Ptnml(0-2): 66, 11856, 35108, 11970, 67
https://tests.stockfishchess.org/tests/view/6a2c4c9c0d5d4b19d0805301
closes https://github.com/official-stockfish/Stockfish/pull/6910
No functional change
The following have zero call sites repo-wide:
SearchManager:🆔 never read or written (also never initialized, nor was it ever used).
Search::Worker::elapsed_time(): never called. PV output uses tm.elapsed_time() (TimeManager) directly. (removed callers on 25361e5)
MovePicker::begin()/end(): unused private accessors. (removed callers on 8c2d21f)
closes https://github.com/official-stockfish/Stockfish/pull/6909
No functional change
Worker::do_move computes the successor hash key via the new
Position::key_after(m) and prefetches the TT entry one full do_move
earlier than the existing prefetch in Position::do_move. key_after does
not model castling, en passant or promotion keys exactly; for rare
moves the prefetch lands on an unused line.
`key_after` has been around since 2014 (https://github.com/official-stockfish/Stockfish/commit/82d065b0) and was removed in (https://github.com/official-stockfish/Stockfish/pull/5770). Adding back `prefetch_key` helps in common, normal moves at the cost of extra compute.
Speedup (PGO vs PGO, interleaved paired bench, n=48 pairs, Apple M2
Pro / apple-silicon): +0.69% [0.47, 0.91]
Passed STC:
https://tests.stockfishchess.org/tests/view/6a291f8d7c758d82accea17f
LLR: 4.24 (-2.94,2.94) <0.00,2.00>
Total: 473504 W: 121250 L: 120228 D: 232026
Ptnml(0-2): 1112, 51137, 131251, 52121, 1131
No functional change
closes https://github.com/official-stockfish/Stockfish/pull/6911
No functional change
This PR fixes the remaining corner cases in the treatment of MultiPV
mated-in PVs, as well as an oversight in #6886. See the discussion in
In particular:
1. `previousScore` and `previousPV` can only be trusted, if that
rootmove was indeed fully searched in the previous iteration.
2. A move beyond `pvIdx` (that was hence not fully searched) may have an
exact loss score that cannot be trusted. So if a MultiPV search gets
aborted while searching `pvIdx`, we mark all the following loss
scores as bounds.
3. The forgotten mate logic also got broken in #6886, because the
`previousPV` of the forgotten mate's bestmove can only be trusted if
that move was fully searched in the previous iteration, something
that is not guaranteed. So we now store both `lastBestMoveScore` and
`lastBestMovePV`.
Here some scenarios for MultiPV = 8 that explain how master was broken:
1. Move A with an inexact mated-in-2 score from the previous iteration
(so outside the top8 moves) gets flushed into the top8 moves for the
current iteration, because the previous top8 move B is now scored as
a mated-in-1. Hence we cannot trust `previousScore` or `previousPV`
for move A, if the search gets aborted while it is being searched.
2. In the scenario above, move B has `Score != -VALUE_INFINITE` and a
mated-in-1 score, which cannot be trusted as it was not fully
searched.
3. Iteration N has bestmove A with mated-in-10, which gets recorded in
`lastBestMoveScore` (renamed from `lastIterationScore`). Iteration 11
forgets the mate and has bestmove B with a cp score, move A may have
an incomplete PV, and may even have a non-mate score. Iteration 12
gets aborted, and in trying to remember the forgotten mate, master
recovers the `previousScore` and `previousPV` of move A, which may be
neither mate nor complete.
Passed STC non-reg:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 69728 W: 17748 L: 17573 D: 34407
Ptnml(0-2): 143, 7571, 19274, 7720, 156
https://tests.stockfishchess.org/tests/view/6a2c40c60d5d4b19d08052f2
closes https://github.com/official-stockfish/Stockfish/pull/6906
No functional change
After merging the HalfKA and Threats accumulators (7c7fe322) and the
subsequent removal of the double-incremental/fused update, a number of
NNUE helpers and fields became unreachable. Each was verified to have
zero callers/readers across the source tree:
- FusedUpdateData logic in FullThreats: the fused-update branch of
append_changed_indices and the FusedUpdateData parameter are unused;
the accumulator update no longer passes fused data.
- FullThreats::requires_refresh: never called. The live king-bucket
refresh check is HalfKAv2_hm::requires_refresh (PSQFeatureSet), used
in nnue_accumulator.
- HalfKAv2_hm::append_active_indices: never called. The live
active-index builder is FullThreats::append_active_indices
(ThreatFeatureSet).
- DirtyThreats::us, prevKsq and ksq: written in do_move but only read by
the now-removed FullThreats::requires_refresh. Removing them also
drops three stores from the do_move path.
- Unused feature Name constants and the unused FtOneVal / HiddenMaxVal
constants in nnue_common.h.
- Two stale feature-header banner comments.
closes https://github.com/official-stockfish/Stockfish/pull/6898
No functional change
This version handles aborting engine processes more gracefully. This
also test the engine prior to use, as the process is nevertheless not
fully robust.
closes https://github.com/official-stockfish/Stockfish/pull/6893
No functional change
The FEN validation check intended to reject pawns on the first or eighth rank uses the `Rank` enum values in a bitwise OR operation:
`if (pieces(PAWN) & (RANK_1 | RANK_8))`
`RANK_1 | RANK_8` evaluates to the integer `0 | 7 == 7` instead of a bitboard, so the expression only tests squares A1, B1 and C1. As a result, unsupported positions with pawns elsewhere on the first or eighth rank are silently accepted. For instance, `position fen 3P3k/8/8/8/8/8/8/3K4 w - - 0 1` is accepted even though the pawn on d8 makes the position unsupported.
Use the `Rank1BB | Rank8BB` bitboard constants so any pawn on the first or eighth rank are correctly rejected.
closes https://github.com/official-stockfish/Stockfish/pull/6887
No functional change
In a recent CCC event, Stockfish (probably through no fault of its own), lost some games on time when it was winning and when it had already found the move that delivers checkmate.
This patch stops the search when TM is active, and when mainthread can be certain that it is impossible to find a better move. That is if (i) it has found mate-in-1, (ii) it has found a mate-in-2 or (iii) it has found a mated-in-1.
patch:
```
position fen 5K2/8/2qk4/2nPp3/3r4/6B1/B7/3R4 w - e6
go wtime 100000000 winc 100000000
info string Available processors: 0-7
info string Using 1 thread
info string NNUE evaluation using nn-71d6d32cb962.nnue (106MiB, (83248, 1024, 31, 32, 1))
info string Network replica 1: Shared memory.
info depth 1 seldepth 3 multipv 1 score mate 1 nodes 30 nps 30000 hashfull 0 tbhits 0 time 1 pv d5e6
bestmove d5e6
```
master:
```
position fen 5K2/8/2qk4/2nPp3/3r4/6B1/B7/3R4 w - e6
go wtime 100000000 winc 100000000
info string Available processors: 0-7
info string Using 1 thread
info string NNUE evaluation using nn-71d6d32cb962.nnue (106MiB, (83248, 1024, 31, 32, 1))
info string Network replica 1: Shared memory.
info depth 1 seldepth 3 multipv 1 score mate 1 nodes 30 nps 15000 hashfull 0 tbhits 0 time 2 pv d5e6
<snip>
info depth 245 seldepth 2 multipv 1 score mate 1 nodes 5886 nps 367875 hashfull 0 tbhits 0 time 16 pv d5e6
bestmove d5e6
```
Note: In MultiPV analysis (extremely rare with TM active), we take the point of view that the user would like to continue to search until none of the PVs can be improved anymore. This means we only stop if the worst searched line is at least a mate-in-2, or if the best searched line is a mated-in-1.
closes https://github.com/official-stockfish/Stockfish/pull/6879
No functional change
Passed STC
https://tests.stockfishchess.org/tests/view/6a2682ce351b79f679cc47c5
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 57248 W: 14730 L: 14399 D: 28119
Ptnml(0-2): 145, 6159, 15698, 6464, 158
Reordering operations in `do_move` allows us to effectively prefetch the TT entry earlier, since the piece moving helpers don't actually modify the position key. I suspect that with threat inputs, `put_piece` and friends got a lot more expensive, and so this helps us a lot.
vondele's machine:
==== master ====
1 Nodes/second : 294311526
2 Nodes/second : 297068312
3 Nodes/second : 297418763
Average (over 3): 296266200
==== pfearly ====
1 Nodes/second : 303986449
2 Nodes/second : 304221719
3 Nodes/second : 305302969
Average (over 3): 304503712 (+2.78%)
Locally, `bench`:
Result of 200 runs
speedup = +0.0158
P(speedup > 0) = 1.0000
As expected it helps even more in a large-hash, NUMA setting.
closes https://github.com/official-stockfish/Stockfish/pull/6891
No functional change
Passed STC (https://tests.stockfishchess.org/tests/view/6a2893ad7c758d82accea129):
LLR: 3.20 (-2.94,2.94) <0.00,2.00>
Total: 23328 W: 6145 L: 5838 D: 11345
Ptnml(0-2): 50, 2463, 6346, 2740, 65
Instead of repeatedly doing the sum HalfKA + threats at the end, it's profitable to simply store one accumulator per side that combines them. This also avoids an extra/load store of an accumulator, and halves the cache footprint of the accumulators.
For full refreshes, we always compute both halfka and threats simultaneously. Any threat full refresh is always a halfka refresh because it occurs when the king crosses the center line, while halfka refreshes are required for ANY king move, so we don't need a separate detection path for threats.
I get about a 2.5% speedup locally with this, but I'd appreciate other ppl's measurements.
closes https://github.com/official-stockfish/Stockfish/pull/6890
No functional change
Adds a `RelaxedAtomic` wrapper around either `T` or `std::atomic<T>` and `USE_SLOPPY_ATOMICS` preprocessor define. The intent of this flag is to allow easy disabling of atomics on WASM, where even relaxed atomics are expensive because all atomics have `seq_cst` semantics.
Passed non regression STC
LLR: 2.99 (-2.94,2.94) <-1.75,0.25>
Total: 50624 W: 12976 L: 12776 D: 24872
Ptnml(0-2): 112, 5445, 14005, 5631, 119
https://tests.stockfishchess.org/tests/view/6a1f690e818cacc1db0ad2c7
Passed non-regression STC SMP
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 163696 W: 41514 L: 41438 D: 80744
Ptnml(0-2): 162, 18272, 44904, 18348, 162
https://tests.stockfishchess.org/tests/view/6a21fb97351b79f679cc44b3
Using this class for the TT also allows us to remove the TSAN suppressions, since the UB is fixed.
closes https://github.com/official-stockfish/Stockfish/pull/6877
No functional change
Fixes#6881.
`timeout_decorator()` used a `ThreadPoolExecutor` context manager around blocking output waits. When `future.result(timeout=...)` timed out, leaving the context manager still waited for the worker thread to finish, so a blocked stdout read could keep the instrumented tests hanging past the configured timeout.
This change removes that executor wrapper for interactive Stockfish output waits. The harness now drains process output on a daemon reader thread, queues received lines, and applies the deadline directly while waiting for the next queued line. `TimeoutException` also initializes the base exception message so failures show useful text.
Validation:
- `python3 -m py_compile tests/testing.py tests/instrumented.py`
- local timeout smoke test: a 0.2s no-output wait raises in ~0.204s
- Stockfish smoke test: startup/`uciok` read succeeds, deliberate no-output wait raises in ~0.205s, engine exits 0
- `make -C src -j4 build`
- `../tests/signature.sh` -> `2814421`
closes https://github.com/official-stockfish/Stockfish/pull/6882
No functional change
This PR introduces the additional `RootMove` attribute `previousPV` so that scores and PVs we send to the GUI in MultiPV analysis always match. This allows us in particular to extend our guarantee of exact mate (and TB win/loss) scores having a complete PV (leading to checkmate in the correct number of plies) to all PV lines. Recall that master fails here, since partially searched root moves may send to the GUI the previous score with the current/modified PV. See #6784.
The PR also uses the new attribute to extend the followPV logic to the analysis of sidelines, building on the idea in #6813 by @joergoster.
Passed non-reg STC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 166880 W: 42357 L: 42282 D: 82241
Ptnml(0-2): 394, 18685, 45177, 18820, 364
https://tests.stockfishchess.org/tests/view/6a0dea55818cacc1db0abb6a
Failed non-reg LTC:
LLR: -2.97 (-2.94,2.94) <-1.75,0.25>
Total: 890520 W: 224168 L: 225282 D: 441070
Ptnml(0-2): 390, 91902, 261789, 90790, 389
https://tests.stockfishchess.org/tests/view/6a1143ad818cacc1db0ac14c
Opening as draft for discussion on how to proceed. In SinglePV analysis, the patch is completely nonfunctional. But it is maybe a (small?) slowdown because of the increased size of `RootMove`. I am not sure if there as an elegant way to enrich the class only for MultiPV analysis (but the switch can happen at any time through the UCI interface), or to mitigate the speed penalty in some other way.
A local speedup test shows only a small slowdown on my system (but still high error bars):
```
sf_base = 1156928 +/- 1459 (95%)
sf_test = 1155885 +/- 1283 (95%)
diff = -1043 +/- 1777 (95%)
speedup = -0.09021% +/- 0.154% (95%)
```
The PR also adds the new MultiPV mate PV correctness check to the CI.
closes https://github.com/official-stockfish/Stockfish/pull/6886
No functional change
Lichess maintains some patches on top of SF dev to get it working with Emscripten. This PR moves some of these patches into SF and adds WASM to CI. It also adds a few changes in places where the x86 intrinsics don't cleanly map onto WebAssembly SIMD instructions; otherwise, we use Emscripten's x86 compatibility layer and take SSE4.1 code paths.
Summary of the compatibility changes:
- Define `wasm32` and `wasm32-relaxed-simd` targets.
- We don't support wasm without SIMD; it'd be a waste of time.
- Add option to disable TBs
- This is required because `tbprobe.cpp` pulls in `mmap`. This option can be used on any target, of course, but it's only enabled by default for wasm.
- Add compilation job + test to CI
And the changes for performance:
- Disable atomics for shared history on wasm
- Atomics are always `seq_cst` there, which can be quite slow (even on the x86, stores are locked `xchg [mem], reg`)
- Add SSE code path to `get_changed_pieces`, modeled after the AVX2 path
- `_mm_mulhi_epi16` has a complicated emulation sequence, so for the pairwise multiplication, use an approach similar to the NEON impl.
- __int128 is gets lowered to runtime functions on wasm, so use the fallback impl for `mul_hi64`
- V8 does a poor job with the NNZ finding, so use a slightly different sequence there
- Add relaxed simd support for `m128_dpbusd`.
Some local perf figures (single-threaded speedtest):
```
wasm
Nodes/second : 902523
sse4.1
Nodes/second : 1155380
avx512icl
Nodes/second : 1676184
```
Further avenues to explore:
- Optimize for performance under V8's experimental AVX revectorizer (Currently it's about +10% in my testing, but could definittely be more)
- Branch hinting. For example, run bench while collecting branch frequency info, then inject it late in the WASM compilation pipeline. I tried this locally and it didn't help much, but maybe I'm missing something.
- PGO. Gives +1.5% NPS locally, but hard to integrate with WASM compilation wrokflows
closes https://github.com/official-stockfish/Stockfish/pull/6875
No functional change
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
