From 879d012275aea45aec255066e6787edae3686ef0 Mon Sep 17 00:00:00 2001
From: Alejandro Cabeza Romero <alex93cabeza@gmail.com>
Date: Fri, 4 Jul 2025 21:52:03 +0200
Subject: [PATCH] Add README to detail building for linux and windows (with
 xcompilation).

---
 circom_circuits/Mantle/README.md | 108 +++++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 circom_circuits/Mantle/README.md

diff --git a/circom_circuits/Mantle/README.md b/circom_circuits/Mantle/README.md
new file mode 100644
index 0000000..a26e258
--- /dev/null
+++ b/circom_circuits/Mantle/README.md
@@ -0,0 +1,108 @@
+# 🛠️ Building
+
+## 🐧 Linux (Fedora)
+1. Generate the C++ code
+    ```bash
+    circom --c --r1cs --no_asm pol.circom
+    ```
+2. Compile
+	```bash
+	make pol
+	```
+
+## 🪟 Windows (Cross-compile from Linux)
+1. Generate the C++ code
+    ```bash
+    circom --c --r1cs --no_asm pol.circom
+    ```
+2. Enter working directory
+    ```bash
+    cd pol_cpp
+    ```
+3. Replace the Makefile
+    The autogenerated `Makefile` does not support cross-compilation. Replace the `Makefile` contents with the following:
+    ```make
+    # ========== General ==========
+
+    DEPS_HPP = circom.hpp calcwit.hpp fr.hpp
+
+    # ========== Native Linux build ==========
+    CXX = g++
+    CXXFLAGS = -std=c++11 -O3 -I.
+    LDFLAGS = -lgmp
+
+    OBJS = main.o calcwit.o fr.o pol.o
+
+    all: pol
+
+    %.o: %.cpp $(DEPS_HPP)
+        $(CXX) -Wno-address-of-packed-member -c $< $(CXXFLAGS)
+
+    pol: $(OBJS)
+        $(CXX) -o $@ $^ $(LDFLAGS)
+
+    # ========== Windows cross-compilation ==========
+
+    CXX_WIN = x86_64-w64-mingw32-g++
+    CC_WIN = x86_64-w64-mingw32-gcc
+    CXXFLAGS_WIN = -std=c++11 -O3 -I. -Iinclude -Duint="unsigned int" -Ideps/mman-win32
+    LDFLAGS_WIN = -L/usr/x86_64-w64-mingw32/sys-root/mingw/lib -lgmp
+
+    WIN_OBJS = main.win.o calcwit.win.o fr.win.o pol.win.o mman.win.o
+
+    %.win.o: %.cpp $(DEPS_HPP)
+        $(CXX_WIN) -Wno-address-of-packed-member -c $< -o $@ $(CXXFLAGS_WIN)
+
+    mman.win.o: deps/mman-win32/mman.c
+        $(CC_WIN) -c $< -o $@
+
+    pol.exe: $(WIN_OBJS)
+        $(CXX_WIN) -o $@ $^ $(LDFLAGS_WIN)
+
+    # ========== Cleanup ==========
+
+    clean:
+        $(RM) *.o *.win.o pol pol.exe
+    ```
+4. Install Dependencies
+    1. Cross-Compiler
+        ```bash
+        sudo dnf install mingw64-gcc mingw64-gcc-c++ # Compiler
+        ```
+    2. `sys/mman.h`
+        ```bash
+        mkdir -p include/sys
+        mkdir -p deps
+        git clone https://github.com/alitrack/mman-win32.git deps/mman-win32
+        cp deps/mman-win32/mman.h ./sys/
+        ```
+    3. `nlohmann/json`
+        ```bash
+        mkdir -p include/nlohmann
+        wget https://raw.githubusercontent.com/nlohmann/json/develop/single_include/nlohmann/json.hpp -O include/nlohmann/json.hpp
+        ```
+    4. `gmp`
+        ```
+        sudo dnf install mingw64-gmp
+        ```
+5. Compile
+    ```bash
+    make pol.exe
+    ```
+6. Bundle
+    1. Copy `.dll`s
+        ```bash
+        cp /usr/x86_64-w64-mingw32/sys-root/mingw/bin/libgcc_s_seh-1.dll \
+           /usr/x86_64-w64-mingw32/sys-root/mingw/bin/libgmp-10.dll \
+           /usr/x86_64-w64-mingw32/sys-root/mingw/bin/libwinpthread-1.dll \
+           /usr/x86_64-w64-mingw32/sys-root/mingw/bin/libstdc++-6.dll \
+           .
+        ```
+    2. Copy `.dat`
+        ```
+        cp pol.dat pol.exe.dat
+        ```
+    3. Bundle
+        ```bash
+        tar -czf pol-windows-bundle.tar.gz pol.exe pol.exe.dat *.dll
+        ```