CMakeLists.txt

cmake_minimum_required(VERSION 3.20)

# ==============================================================================
# Toolchain & Project Setup
# ==============================================================================
set(CMAKE_SYSTEM_NAME Generic)
set(CMAKE_SYSTEM_PROCESSOR arm)
set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)

set(TC_PREFIX arm-none-eabi-)
set(CMAKE_C_COMPILER ${TC_PREFIX}gcc)
set(CMAKE_CXX_COMPILER ${TC_PREFIX}g++)
set(CMAKE_ASM_COMPILER ${TC_PREFIX}gcc)
set(CMAKE_OBJCOPY ${TC_PREFIX}objcopy)
set(CMAKE_SIZE ${TC_PREFIX}size)

project(mos-renode C CXX ASM)

# ==============================================================================
# Simplified Submodule Automation (Nested Support)
# ==============================================================================
find_package(Git QUIET)

# Define key paths
set(CORE_DIR "${CMAKE_SOURCE_DIR}/core")
set(ETL_DIR "${CORE_DIR}/external/etl")

if(GIT_FOUND AND EXISTS "${CMAKE_SOURCE_DIR}/.git")
    # Check if 'core' is populated OR if 'etl' inside core is populated
    if(NOT EXISTS "${CORE_DIR}/kernel/printf.c" OR NOT EXISTS "${ETL_DIR}/CMakeLists.txt")
        message(STATUS "Submodules missing. Initializing recursively...")

        # Standard initialization: Pull the specific commit recorded in the superproject
        execute_process(
            COMMAND ${GIT_EXECUTABLE} submodule update --init --recursive
            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
            RESULT_VARIABLE git_res
        )

        # Update to Master: If initialization succeeded, force 'core' to latest master
        if(git_res EQUAL 0)
            message(STATUS "Switching 'core' submodule to latest master branch...")

            # Switch 'core' from detached HEAD to master branch
            execute_process(
                COMMAND ${GIT_EXECUTABLE} checkout master
                WORKING_DIRECTORY ${CORE_DIR}
            )

            # Pull the latest changes from remote master
            execute_process(
                COMMAND ${GIT_EXECUTABLE} pull origin master
                WORKING_DIRECTORY ${CORE_DIR}
            )

            # Update nested submodules inside 'core' (in case master has new dependencies)
            execute_process(
                COMMAND ${GIT_EXECUTABLE} submodule update --init --recursive
                WORKING_DIRECTORY ${CORE_DIR}
            )
        endif()

        # Fallback: If 'etl' was never added to 'core' as a submodule, add it now
        if(EXISTS "${CORE_DIR}" AND NOT EXISTS "${ETL_DIR}/CMakeLists.txt")
            message(STATUS "Adding ETL as nested submodule in core...")
            execute_process(
                COMMAND ${GIT_EXECUTABLE} submodule add -f https://github.com/ETLCPP/etl.git external/etl
                WORKING_DIRECTORY ${CORE_DIR}
            )
            execute_process(COMMAND ${GIT_EXECUTABLE} submodule update --init --recursive WORKING_DIRECTORY ${CMAKE_SOURCE_DIR})
        endif()
    endif()
endif()

# Use EXCLUDE_FROM_ALL to prevent building ETL tests or examples
add_subdirectory(${ETL_DIR} EXCLUDE_FROM_ALL)

# ==============================================================================
# Target Configuration
# ==============================================================================
set(TARGET_NAME mos-renode)

# CONFIGURE_DEPENDS: Automatically re-scan for new files during build, no manual refresh needed
file(GLOB_RECURSE DRIVER_SOURCES CONFIGURE_DEPENDS
    "vendor/Core/Src/*.c"
    "vendor/Drivers/STM32F4xx_HAL_Driver/Src/*.c"
)

add_executable(${TARGET_NAME}.elf
    core/kernel/printf.c
    core/kernel/syscall.c
    app/main.cpp
    vendor/startup_stm32f407xx.s
    ${DRIVER_SOURCES}
)

# ==============================================================================
# Build Options
# ==============================================================================
target_compile_features(${TARGET_NAME}.elf PRIVATE c_std_17 cxx_std_23)
target_compile_definitions(${TARGET_NAME}.elf PRIVATE STM32F407xx USE_FULL_LL_DRIVER USE_HAL_DRIVER)

target_include_directories(${TARGET_NAME}.elf PRIVATE
    vendor
    vendor/Core/Inc
    vendor/Core/Src
    vendor/Drivers/STM32F4xx_HAL_Driver/Inc
    vendor/Drivers/CMSIS/Include
    vendor/Drivers/CMSIS/Device/ST/STM32F4xx/Include

    core
    core/kernel
    core/kernel/data_type
    core/arch

    app
)

# ==============================================================================
# Hardware Definitions & MCU Flags
# ==============================================================================
set(MCU_FLAGS
    -mcpu=cortex-m4
    -mthumb
    -mfpu=fpv4-sp-d16
    -mfloat-abi=hard
) # FPU Enabled

# set(MCU_FLAGS
# -mcpu=cortex-m4
# -mthumb
# ) # FPU Disabled

# Consolidate general compilation flags
target_compile_options(${TARGET_NAME}.elf PRIVATE
    ${MCU_FLAGS}
    -Os -Wall -g
    -ffunction-sections -fdata-sections
    -funsigned-char -fno-exceptions
    --specs=nano.specs
    -flto
    $<$<COMPILE_LANGUAGE:CXX>:-fno-rtti -fcoroutines -fno-use-cxa-atexit>
    $<$<COMPILE_LANGUAGE:C>:-Wno-deprecated-volatile>
)

# Linker script configuration
set(LINKER_SCRIPT "${CMAKE_SOURCE_DIR}/vendor/STM32F407VGTx_FLASH.ld")

target_link_libraries(${TARGET_NAME}.elf PRIVATE etl::etl)
target_link_options(${TARGET_NAME}.elf PRIVATE
    ${MCU_FLAGS}
    -T${LINKER_SCRIPT}
    -Wl,--gc-sections --specs=nosys.specs --specs=nano.specs
    -Wl,--print-memory-usage
    -flto
    -Wl,-Map=${CMAKE_BINARY_DIR}/${TARGET_NAME}.map
)

# ==============================================================================
# Post-Build Steps
# ==============================================================================
add_custom_command(TARGET ${TARGET_NAME}.elf POST_BUILD
    COMMAND ${CMAKE_OBJCOPY} -O ihex $<TARGET_FILE:${TARGET_NAME}.elf> ${TARGET_NAME}.hex
    COMMAND ${CMAKE_OBJCOPY} -O binary $<TARGET_FILE:${TARGET_NAME}.elf> ${TARGET_NAME}.bin
    COMMAND ${CMAKE_SIZE} $<TARGET_FILE:${TARGET_NAME}.elf>
    COMMENT "Generating HEX, BIN, and size report..."
)