Add riscv32 compile support

CMakeLists.txt

@@ -60,6 +60,8 @@ elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(arm.*|ARM.*)")
   set(ARCH "arm")
 elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^riscv64")
   set(ARCH "riscv64")
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^riscv32")
+  set(ARCH "riscv32")
 elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^loongarch64")
   set(ARCH "loong64")
 else()
@@ -279,6 +281,9 @@ else()
   elseif(ARCH STREQUAL "riscv64")
     add_compile_options(-march=rv64gc)
     add_compile_options(-mabi=lp64d)
+  elseif(ARCH STREQUAL "riscv32")
+    add_compile_options(-march=rv32gc)
+    add_compile_options(-mabi=ilp32d)
   elseif(ARCH STREQUAL "loong64")
     add_compile_options(-march=loongarch64)
     add_compile_options(-mabi=lp64d)

cmake/toolchains/riscv32-linux-gnu.cmake

@@ -0,0 +1,43 @@
+#
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+#
+
+if(UHDR_BUILD_CMAKE_TOOLCHAINS_RISCV32_LINUX_GNU_CMAKE_)
+  return()
+endif()
+
+set(UHDR_BUILD_CMAKE_TOOLCHAINS_RISCV32_LINUX_GNU_CMAKE_ 1)
+
+set(CMAKE_SYSTEM_NAME "Linux")
+set(CMAKE_SYSTEM_PROCESSOR "riscv32")
+
+if("${CROSS}" STREQUAL "")
+  set(CROSS riscv32-linux-gnu-)
+endif()
+
+if(NOT CMAKE_C_COMPILER)
+  set(CMAKE_C_COMPILER ${CROSS}gcc)
+endif()
+if(NOT CMAKE_CXX_COMPILER)
+  set(CMAKE_CXX_COMPILER ${CROSS}g++)
+endif()
+if(NOT AS_EXECUTABLE)
+  set(AS_EXECUTABLE ${CROSS}as)
+endif()
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)

docs/building.md

@@ -271,6 +271,31 @@ This will generate the following files under `build_directory`:
 **ultrahdr_app** - sample application <br>
 **ultrahdr_unit_test** - unit tests <br>
 
+#### Target - Linux Platform - RISC-V Arch (32 bit)
+
+Install the prerequisite packages before building:
+
+```sh
+# Download from https://github.com/riscv-collab/riscv-gnu-toolchain/releases
+sudo ln -s {your_dir}/riscv/bin/riscv32-unknown-linux-gnu-g++ /usr/bin/riscv32-linux-gnu-g++
+sudo ln -s {your_dir}/riscv/bin/riscv32-unknown-linux-gnu-gcc /usr/bin/riscv32-linux-gnu-gcc
+```
+
+Compile:
+
+```sh
+cmake -G Ninja -DCMAKE_TOOLCHAIN_FILE=../cmake/toolchains/riscv32-linux-gnu.cmake -DUHDR_BUILD_DEPS=1 ../
+ninja
+```
+
+This will generate the following files under `build_directory`:
+
+**libuhdr.so.{version}** - Shared library for the libuhdr API <br>
+**libuhdr.so** - Symlink to shared library <br>
+**libuhdr.a** - Static link library for the libuhdr API <br>
+**ultrahdr_app** - sample application <br>
+**ultrahdr_unit_test** - unit tests <br>
+
 #### Target - Linux Platform - LOONG Arch (64 bit)
 
 Install the prerequisite packages before building: