Add Armv7 support to Build docs
@@ -105,6 +105,30 @@ To enable this binary variant add `-DISA_NONE=ON` to the CMake command line
when configuring. It is NOT recommended to use this for production; it is
significantly slower than the vectorized SIMD builds.
+### Armv7 builds
+
+The build system includes support for building for Armv7 32-bit binaries on
+Linux and macOS, using GCC 9.3 or higher, or Clang 9 or higher. The `armv7`
+build uses the soft-float ABI and `armv7hf` uses the hard-float ABI.
+
+:warning: Armv7 NEON is not IEEE-754 strict compliant, so these builds may not
+be invariant with other build targets.
+
+We tested these builds using the following cross-compilers on Ubuntu 20.04:
+
+* `armv7`: arm-linux-gnueabi-g++-9 (v 9.3.0)
+* `armv7hf`: arm-linux-gnueabihf-g++-9 (v 9.3.0)
+
+```shell
+# Arm armv7 using the soft-float ABI
+cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=./ \
+ -DARCH=armv7 -DISA_NEON=ON ..
+
+# Arm armv7hf using the hard-float ABI
+cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=./ \
+ -DARCH=armv7hf -DISA_NEON=ON ..
+```
+
### Build Types
We support and test the following `CMAKE_BUILD_TYPE` options.
