4.3 Board configuration file

The board configuration file is where board-specific configuration details are stored. A board configuration file contains all the higher-level configuration settings. There is a rough inheritance scheme, where it is possible to derive a new board description file from an existing one. There are also collections of custom procedures for common environments. For more information on adding a new board config file, see Adding a new board.

An example board configuration file for a GNU simulator is as follows. set_board_info is a procedure that sets the field name to the specified value. The procedures mentioned in brackets are helper procedures. These are used to find parts of a toolchain required to build an executable image that may reside in various locations. This is mostly of use when the startup code, the standard C libraries, or the toolchain itself is part of your build tree.

Example file

# This is a list of toolchains that are supported on this board.
set_board_info target_install {sparc64-elf}

# Load the generic configuration for this board. This will define any
# routines needed by the tool to communicate with the board.
load_generic_config "sim"

# We need this for find_gcc and *_include_flags/*_link_flags.
load_base_board_description "basic-sim"

# Use long64 by default.
process_multilib_options "long64"

setup_sim sparc64

# We only support newlib on this target. We assume that all multilib
# options have been specified before we get here.

set_board_info compiler "[find_gcc]"
set_board_info cflags "[libgloss_include_flags] [newlib_include_flags]"
set_board_info ldflags "[libgloss_link_flags] [newlib_link_flags]"
# No linker script.
set_board_info ldscript ""

# Used by a few gcc.c-torture testcases to delimit how large the
# stack can be.
set_board_info gcc,stack_size 16384
# The simulator doesn't return exit status and we need to indicate this
# the standard GCC wrapper will work with this target.
set_board_info needs_status_wrapper 1
# We can't pass arguments to programs.
set_board_info noargs 1

There are five helper procedures used in this example:

• find_gcc looks for a copy of the GNU compiler in your build tree, or it uses the one in your path. This will also return the proper transformed name for a cross compiler if you whole build tree is configured for one. DejaGnu will use this procedure to locate a compiler if the compiler field is not set.
• libgloss_include_flags returns the flags to compile using libgloss, the GNU board support package (BSP).
• libgloss_link_flags returns the flags to link an executable using libgloss.
• newlib_include_flags returns the flags to compile using newlib, a re-entrant standard C library for embedded systems comprising of non-GPL’d code
• newlib_link_flags returns the flags to link an executable with newlib.