stockfish/README.md

# Stockfish for Cartesi RISC-V Machine Emulator
This branch contains patchlets to compile a RISC-V 64-bit build of
stockfish to run under the Cartesi machine emulator.

# Setup Cartesi SDK
Build using Cartesi GCC. I just copied them from the docker build
and put them in my path (outside of the docker). It's probably
easiest to build in the SDK docker.

```
git clone --recursive https://github.com/cartesi/machine-emulator-sdk
```

You should be able
to run this command OK before proceeding:

```
riscv64-cartesi-linux-gnu-gcc --version
```

# Build
Note, the Makefile kludge disables things like "tests".

Run this to build stockfish binary for riscv64 using Cartesi GCC toolchain:

```
git clone https://spacecruft.org/deepcrayon/stockfish
cd stockfish/src
make -j build ARCH=riscv64 COMP=riscv64-cartesi-linux-gnu-gcc COMPCXX=riscv64-cartesi-linux-gnu-g++
```

# Build Disk Images for Cartesi Emulator

```
# Go back to top level directory in this git repo:
cd ..

# Copy newly built stockfish for cartesi disk image:
cp -p src/stockfish cartesi/img/stockfish

# Make 50 megabyte ext2 disk image with stockfish and shell script
genext2fs -b 51200 -d cartesi/img cartesi/stockfish.ext2
```

# Run Stockfish in Emulator
To run the disk images, using upstream rootfs:

```
cartesi-machine								\
	--ram-length=256Mi						\
	--flash-drive=label:stockfish,filename:cartesi/stockfish.ext2	\
	--flash-drive=label:root,filename:/opt/cartesi/share/images/rootfs.ext2	\
	-- /mnt/stockfish/stockfish.sh
```

# Emulator Output
This takes ~3 minutes to run:

```
         .
        / \
      /    \
\---/---\  /----\
 \       X       \
  \----/  \---/---\
       \    / CARTESI
        \ /   MACHINE
         '


Stockfish running under Cartesi virtual machine

Stockfish 161121 by the Stockfish developers (see AUTHORS file)

option name Debug Log File type string default 
option name Threads type spin default 1 min 1 max 512
option name Hash type spin default 16 min 1 max 33554432
option name Clear Hash type button
option name Ponder type check default false
option name MultiPV type spin default 1 min 1 max 500
option name Skill Level type spin default 20 min 0 max 20
option name Move Overhead type spin default 10 min 0 max 5000
option name Slow Mover type spin default 100 min 10 max 1000
option name nodestime type spin default 0 min 0 max 10000
option name UCI_Chess960 type check default false
option name UCI_AnalyseMode type check default false
option name UCI_LimitStrength type check default false
option name UCI_Elo type spin default 1350 min 1350 max 2850
option name UCI_ShowWDL type check default false
option name SyzygyPath type string default <empty>
option name SyzygyProbeDepth type spin default 1 min 1 max 100
option name Syzygy50MoveRule type check default true
option name SyzygyProbeLimit type spin default 7 min 0 max 7
option name Use NNUE type check default true
option name EvalFile type string default nn-13406b1dcbe0.nnue
uciok

Halted
Cycles: 3142947347
```

# Store Machine State
Instead of fully booting, a RAM image can be loaded and the
CPU set to a cycle, such as 3142947347.

```
cartesi-machine								\
	--max-mcycle=3142947347						\
	--store=cartesi/stockfish-ram					\
	--ram-length=256Mi						\
	--flash-drive=label:stockfish,filename:cartesi/stockfish.ext2	\
	--flash-drive=label:root,filename:/opt/cartesi/share/images/rootfs.ext2	\
	-- /mnt/stockfish/stockfish.sh
```

# TODO

* Make image of RAM with stockfish already run once and loaded.

* Fix tests.

# Upstream
See:

* README-upstream.md

* https://github.com/official-stockfish/Stockfish

* https://stockfishchess.org/

# Cartesi
See:

* https://cartesi.io/en/docs/intro/

* https://github.com/cartesi/machine-emulator/

# Copying
Same as upstream Stockfish, GPL v3.

# Contact
```
# y@deepcrayon.fish or jebba in Cartesi/Stockfish discord

```