Development:ARM64EC - Revision history

Sonicadvance1 at 21:15, 7 October 2025

2025-10-07T21:15:16Z

Neobrain: BUILD_TESTS -> BUILD_TESTING

2025-09-11T12:11:37Z

BUILD_TESTS -> BUILD_TESTING

Neobrain at 09:41, 14 July 2025

2025-07-14T09:41:50Z

Sonicadvance1 at 17:13, 8 July 2025

2025-07-08T17:13:52Z

Sonicadvance1 at 17:03, 8 July 2025

2025-07-08T17:03:09Z

Neobrain at 08:19, 27 June 2025

2025-06-27T08:19:10Z

Sonicadvance1: /* Build directions */

2025-02-06T19:30:28Z

Build directions

Sonicadvance1: /* Wine */

2025-02-06T19:27:11Z

Wine

Sonicadvance1: /* Build directions */

2025-02-06T19:26:59Z

Build directions

Sonicadvance1: /* Build directions */

2025-02-06T19:26:00Z

Build directions

@@ Line 4: / Line 4: @@
 ==== Toolchain ====
-Scripts and instructions to build an ARM64EC toolchain can be found [https://github.com/bylaws/llvm-mingw here], with prebuilt binaries for ARM64/x86 hosts on the [https://github.com/bylaws/llvm-mingw/releases/tag/20240929 releases page]. Once built/downloaded, add it to your environment with
+Scripts and instructions to build an ARM64EC toolchain can be found [https://github.com/bylaws/llvm-mingw here], with prebuilt binaries for ARM64/x86 hosts on the [https://github.com/bylaws/llvm-mingw/releases releases page]. Once built/downloaded, add it to your environment with
   export PATH="<path to toolchain>/bin:$PATH"
 note the toolchain must come before all other path entries as it needs to override the host ar binary.

@@ Line 24: / Line 24: @@
   mkdir build-arm64ec
   cd build-arm64ec
-  cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../Data/CMake/toolchain_mingw.cmake -DCMAKE_INSTALL_LIBDIR=/usr/lib/wine/aarch64-windows -DENABLE_LTO=False -DMINGW_TRIPLE=arm64ec-w64-mingw32 -DBUILD_TESTS=False -DENABLE_JEMALLOC_GLIBC_ALLOC=False -DCMAKE_INSTALL_PREFIX=/usr ..
+  cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../Data/CMake/toolchain_mingw.cmake -DCMAKE_INSTALL_LIBDIR=/usr/lib/wine/aarch64-windows -DENABLE_LTO=False -DMINGW_TRIPLE=arm64ec-w64-mingw32 -DBUILD_TESTING=False -DENABLE_JEMALLOC_GLIBC_ALLOC=False -DCMAKE_INSTALL_PREFIX=/usr ..
   ninja
   sudo ninja install
@@ Line 30: / Line 30: @@
   mkdir build-wow64
   cd build-wow64
-  cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../Data/CMake/toolchain_mingw.cmake -DCMAKE_INSTALL_LIBDIR=/usr/lib/wine/aarch64-windows -DENABLE_LTO=False -DMINGW_TRIPLE=aarch64-w64-mingw32 -DBUILD_TESTS=False -DENABLE_JEMALLOC_GLIBC_ALLOC=False -DCMAKE_INSTALL_PREFIX=/usr ..
+  cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../Data/CMake/toolchain_mingw.cmake -DCMAKE_INSTALL_LIBDIR=/usr/lib/wine/aarch64-windows -DENABLE_LTO=False -DMINGW_TRIPLE=aarch64-w64-mingw32 -DBUILD_TESTING=False -DENABLE_JEMALLOC_GLIBC_ALLOC=False -DCMAKE_INSTALL_PREFIX=/usr ..
   ninja
   sudo ninja install

@@ Line 59: / Line 59: @@
 Unlike Linux FEX, the Windows FEX modules purely handle CPU emulation, with syscall translation being done on either the wine side (WOW64) or ABI (ARM64EC). This is similarly the case for wine's unixcalls and as a result native ARM64 variants can be used for all .so libraries (Vulkan, wine, etc.) dropping the need for an x86 rootfs and FEX-side thunking.
-WOW64 is the mechanism to run 32-bit applications on 64-bit platforms: Almost all Windows system libraries are emulated from their original x86 builds here. Only {unix,sys}calls are adapted on-the-fly by injecting thunks. For developers, Microsoft distributes native ARM64 builds of the system libraries as well, but that isn't a concern for FEX.
+WOW64 (Windows 32-bit On Windows 64-bit) is the mechanism to run 32-bit applications on 64-bit platforms: All system libraries are built as x86 and emulated. Any 32-bit syscalls they use are adapted on-the-fly to 64-bit equivalents by injecting thunks.
-ARM64EC on the other hand deals with 64-bit applications and avoids emulation overhead by using a dedicated set of system libraries compiled for ARM64 with a custom ABI. This ARM64EC ABI is designed to be callable from recompiled x86_64 code, so that application binaries can use the non-emulated system libraries directly. To ease application porting, Microsoft extended the PE format ("ARM64X") to combine ARM64EC code with regular ARM64 code in a single binary file (leveraging linker relocations for function prologues/epilogues to avoid duplicating any code). This extension allows a single set of system libraries to be used both for native ARM64 applications and for emulated x86 ones, without needing to distribute any of the original x86 system libraries at all.
+ARM64EC (Emulation Compatible) on the other hand deals with 64-bit applications and avoids emulation overhead by using a dedicated set of system libraries compiled for ARM64 with the custom ARM64EC ABI. This ABI is designed to be callable from recompiled x86_64 code in order to allow a mix-and-match of native and emulated code. To avoid needing both a set of ARM64EC and ARM64 system libraries, ARM64X is introduced: It uses linker relocations to combine ARM64EC code and regular ARM64 code in a single binary file, which can be used both by standard Windows-on-Arm applications and emulated x86_64 ones.
 The following pages serve as a good reference:

← Older revision		Revision as of 17:13, 8 July 2025
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	Of note is the fact that FEX needs to run in a very reduced Windows environment - due to how early it is loaded it can only depend on ntdll and not say the system CRT. This is worked around by implementing/stubbing the subset of the CRT/Windows APIs necessary for FEX to run/link purely ontop of ntdll (see Common/Windows/{WinAPI,CRT}).		Of note is the fact that FEX needs to run in a very reduced Windows environment - due to how early it is loaded it can only depend on ntdll and not say the system CRT. This is worked around by implementing/stubbing the subset of the CRT/Windows APIs necessary for FEX to run/link purely ontop of ntdll (see Common/Windows/{WinAPI,CRT}).
		+
		+	=== Building problems ===
		+	==== `bytes of instructions in range, but .seh directives corresponding to` ====
		+	This is seemingly caused by the `-mcpu` tune option, pass to cmake `-DTUNE_CPU=none`

@@ Line 24: / Line 24: @@
   mkdir build-arm64ec
   cd build-arm64ec
-  cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../toolchain_mingw.cmake -DCMAKE_INSTALL_LIBDIR=/usr/lib/wine/aarch64-windows -DENABLE_LTO=False -DMINGW_TRIPLE=arm64ec-w64-mingw32 -DBUILD_TESTS=False -DENABLE_JEMALLOC_GLIBC_ALLOC=False -DCMAKE_INSTALL_PREFIX=/usr ..
+  cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../Data/CMake/toolchain_mingw.cmake -DCMAKE_INSTALL_LIBDIR=/usr/lib/wine/aarch64-windows -DENABLE_LTO=False -DMINGW_TRIPLE=arm64ec-w64-mingw32 -DBUILD_TESTS=False -DENABLE_JEMALLOC_GLIBC_ALLOC=False -DCMAKE_INSTALL_PREFIX=/usr ..
   ninja
   sudo ninja install
@@ Line 30: / Line 30: @@
   mkdir build-wow64
   cd build-wow64
-  cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../toolchain_mingw.cmake -DCMAKE_INSTALL_LIBDIR=/usr/lib/wine/aarch64-windows -DENABLE_LTO=False -DMINGW_TRIPLE=aarch64-w64-mingw32 -DBUILD_TESTS=False -DENABLE_JEMALLOC_GLIBC_ALLOC=False -DCMAKE_INSTALL_PREFIX=/usr ..
+  cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../Data/CMake/toolchain_mingw.cmake -DCMAKE_INSTALL_LIBDIR=/usr/lib/wine/aarch64-windows -DENABLE_LTO=False -DMINGW_TRIPLE=aarch64-w64-mingw32 -DBUILD_TESTS=False -DENABLE_JEMALLOC_GLIBC_ALLOC=False -DCMAKE_INSTALL_PREFIX=/usr ..
   ninja
   sudo ninja install

@@ Line 12: / Line 12: @@
 [https://gitlab.winehq.org/wine/wine Upstream] wine has various things missing for full FEX/ARM64EC support, while it can be used, [https://github.com/bylaws/wine/tree/upstream-arm64ec my fork] will give the best results for now. Make sure to install the deps listed [https://salsa.debian.org/wine-team/wine/-/blob/debian/9.0_repack-4/debian/control.in?ref_type=tags#L13 here] before building with the ARM64EC toolchain.
-   ./configure --enable-archs=arm64ec,aarch64,i386 --with-mingw=clang --disable-tests
+   ./configure --enable-archs=arm64ec,aarch64,i386 --prefix=/usr --with-mingw=clang --disable-tests
    make -j$(nproc)
    sudo --preserve-env=PATH make install -j$(nproc)
 ==== FEX ====