Compile applications

Warning

The RISC-V toolchain environment variable name has changed. Use RISCV_XHEEP instead of RISCV to avoid conflicts with other projects. If you previously exported RISCV for X-HEEP, update your shell initialization files (e.g., ~/.bashrc, ~/.zshrc) or environment modules to export RISCV_XHEEP and remove or adjust any old RISCV definitions accordingly.

All software applications can be found in sw/applications. These can be compiled with the app target of the top-level makefile of X-HEEP. To compile the hello world application with default parameters, just type:

make app

This will create the executable file to be loaded in your target system (ASIC, FPGA, Simulation). X-HEEP is using CMake to compile and link. Thus, the generated files after having compiled and linked are under sw\build.

Warning

Don’t forget to set the RISCV_XHEEP env variable to the compiler folder (without the /bin included).

You can select the application to run, the target, compiler, etc. by modifying the parameters. The compiler flags explicitly specified by the user will override those already existing (e.g. the default optimization level is -O2, passing COMPILER_FLAGS=-Os will override the -O2). This can be used to pass preprocessor definitions (e.g. passing make app COMPILER_FLAGS=-DENABLE_PRINTF is equivalent to adding #define ENABLE_PRINTF on all included files).

app PROJECT=<folder_name_of_the_project_to_be_built> TARGET=sim(default),systemc,pynq-z2,nexys-a7-100t,genesys2,aup-zu3,zcu102,zcu104 LINKER=on_chip(default),flash_load,flash_exec COMPILER=gcc(default),clang COMPILER_PREFIX=riscv32-corev-(default),riscv32-unknown- ARCH=rv32imc_zicsr(default),<any_RISC-V_ISA_string_supported_by_the_CPU> 

Params:
    - PROJECT (ex: <folder_name_of_the_project_to_be_built>) 
    - TARGET (ex: sim(default),systemc,pynq-z2,nexys-a7-100t,genesys2,aup-zu3,zcu102,zcu104) 
    - LINKER (ex: on_chip(default),flash_load,flash_exec) 
    - COMPILER (ex: gcc(default),clang) 
    - COMPILER_PREFIX (ex: riscv32-corev-(default),riscv32-unknown-) 
    - COMPILER_FLAGS (ex: -O0, "-Wall -l<library>")
    - ARCH (ex: rv32imc_zicsr(default),<any_RISC-V_ISA_string_supported_by_the_CPU>)

Note

You can run make help or make to see the most up-to-date documentation for the makefile. This includes the parameters available for this command, as well as the documentation for all other commands.

For instance, to compile the hello world app with the default compiler for the pynq-z2 FPGA, just run:

make app PROJECT=hello_world TARGET=pynq-z2

Using the standard GCC or Clang compilers

If you want to use the standard GCC or Clang toolchains, make sure to point the RISCV_XHEEP env variable to the corresponding compiler, then just run:

make app COMPILER=gcc COMPILER_PREFIX=riscv32-unknown- ARCH=rv32imc_zicsr

make app COMPILER=clang COMPILER_PREFIX=riscv32-unknown- ARCH=rv32imc_zicsr

Using the OpenHW Group compiler with PULP extensions

If you want to use the OpenHW Group GCC compiler with CORE_PULP extensions, make sure to point the RISCV_XHEEP env variable to the OpenHW Group compiler, then just run:

make app COMPILER=gcc COMPILER_PREFIX=riscv32-corev- ARCH=rv32imc_zicsr_zifencei_xcvhwlp_xcvmem_xcvmac_xcvbi_xcvalu_xcvsimd_xcvbitmanip

Using the RVE RISC-V extensions

RVE extensions are supported by the standard compiler when using the appropriate ARCH and ABI options (see the setup page for details). Ensure that the RISCV_XHEEP environment variable points to the compiler configured for the correct ABI, which operates only on registers x0–x15. By default, C code is compiled without using registers x16–x31. The X-HEEP bootrom and crt0 have also been implemented in assembly without relying on those registers. If your application needs to detect whether the RVE extensions are in use, the compiler automatically defines the __riscv_32e macro. This is used, for example, in the power manager’s HAL for context save/restore operations, ensuring that registers x16–x31 are ignored when applicable.

make app ARCH=rv32emc_zicsr

Compiling FreeRTOS based applications

X-HEEP supports FreeRTOS based applications. Please see sw\applications\example_freertos_blinky.

After that, you can run the command to compile and link the FreeRTOS based application. Please also set ‘LINKER’ and ‘TARGET’ parameters if needed.

make app PROJECT=example_freertos_blinky

The main FreeRTOS configuration is allocated under sw\freertos, in FreeRTOSConfig.h. Please, change this file based on your application requirements. Moreover, FreeRTOS is being fetched from ‘https://github.com/FreeRTOS/FreeRTOS-Kernel.git’ by CMake. Specifically, ‘V10.5.1’ is used. Finally, the fetch repository is located under sw\build\_deps after building.