Using XMOS Makefiles

An application is made up of source code unique to the application and, optionally, source code from modules of common code or binary libraries. When developing an application, the working area is described in terms of workspaces, projects, applications and modules.

Workspace

A workspace is a container for several projects.

Projects

A project is a directory possibly containing several applications and modules plus other files relating to a particular project. A project may contain the code for a particular board or reference design or be a software component containing modules for other projects to use.

Applications

An application is a directory containing source files and a Makefile that builds into a single executable (.xe) file. By convention application directories start with the prefix app_. These applications appear at the top level in the project explorer in the XDE.

Modules

A module is a directory containing source files and/or binary libraries. The source does not build to anything by itself but can be used by applications. by convention module directories start with the prefix module_. These modules appear at the top level in the project explorer in the XDE.

Example Structure

sw_avb/
    app_avb_demo1/
    app_avb_demo2/
    module_avb1/
    module_avb2/
    doc/
sc_xtcp/
    module_xtcp/
    module_zeroconf/
sc_ethernet/
    module_ethernet/

app_avb_demo1/
app_avb_demo2/
module_avb1/
module_avb2/
doc/
module_xtcp/
module_zeroconf/
module_ethernet/

Every application directory should contain a file named Makefile that includes the common XMOS Makefile. The common Makefile controls the build, by default including all source files within the application directory and its sub-directories. The application Makefile supports the following variable assignments.

• XCC_FLAGS[_config]

  Specifies the flags passed to xcc during the build. This option sets the flags for the particular build configuration config. If no suffix is given, it sets the flags for the default build configuration.

• XCC_C_FLAGS[_config]

  If set, these flags are passed to xcc instead of XCC_FLAGS for all .c files. This option sets the flags for the particular build configuration config. If no suffix is given, it sets the flags for the default build configuration.

• XCC_ASM_FLAGS[_config]

  If set, these flags are passed to xcc instead of XCC_FLAGS for all .s or .S files. This option sets the flags for the particular build configuration config. If no suffix is given, it sets the flags for the default build configuration.

• XCC_MAP_FLAGS[_config]

  If set, these flags are passed to xcc for the final link stage instead of XCC_FLAGS. This option sets the flags for the particular build configuration config. If no suffix is given, it sets the flags for the default build configuration.

• XCC_FLAGS_filename

  Overides the flags passed to xcc for the filename specified. This option overides the flags for all build configurations.

• VERBOSE

  If set to 1, enables verbose output from the make system.

• SOURCE_DIRS

  Specifies the list of directories, relative to the application directory, that have their contents compiled. By default all directories are included.

• INCLUDE_DIRS

  Specifies the directories to look for include files during the build. By default all directories are included.

• LIB_DIRS

  Specifies the directories to look for libraries to link into the application during the build. By default all directories are included.

• EXCLUDE_FILES

  Specifies a space-separated list of source file names (not including their path) that are not compiled into the application.

• USED_MODULES

  Specifies a space-separated list of module directories that are compiled into the application. The module directories should always be given without their full path irrespective of which project they come from, for example:

  USED_MODULES = module_xtcp module_ethernet
  

• MODULE_LIBRARIES

  This option specifies a list of preferred libraries to use from modules that specify more than one. See Using XMOS Makefiles to create binary libraries for details.

As well as each application having its own Makefile, the project should have a Makefile at the top-level. This Makefile controls building the applications within the project. It has one variable assignment within it to do this:

• BUILD_SUBDIRS

  Specifies a space-separated list of application directories to build.

Each module directory should contain a file named module_build_info. This file informs an application how to build the files within the module if the application includes the module in its build. It can optionally contain several of the following variable assignments.

• DEPENDENT_MODULES

  Specifies the dependencies of the module. When an application includes a module it will also include all its dependencies.

• MODULE_XCC_FLAGS

  Specifies the options to pass to xcc when compiling source files from within the current module. The definition can reference the XCC_FLAGS variable from the application Makefile, for example:

  MODULE_XCC_FLAGS = $(XCC_FLAGS) -O3
  

• MODULE_XCC_XC_FLAGS

  If set, these flags are passed to xcc instead of MODULE_XCC_FLAGS for all .xc files within the module.

• MODULE_XCC_C_FLAGS

  If set, these flags are passed to xcc instead of MODULE_XCC_FLAGS for all .c files within the module.

• MODULE_XCC_ASM_FLAGS

  If set, these flags are passed to xcc instead of MODULE_XCC_FLAGS for all .s or .S files within the module.

• OPTIONAL_HEADERS

  Specifies a particular header file to be an optional configuration header. This header file does not exist in the module but is provided by the application using the module. The build system will pass the a special macro __filename_h_exists__ to xcc if the application has provided this file. This allows the module to provide default configuration values if the file is not provided.