crosstool-ng/config/target.in

# Target definition: architecture, optimisations, etc...

menu "Target options"

comment "General target options"

config ARCH
    string
    default "arm"     if ARCH_ARM
    default "mips"    if ARCH_MIPS
    default "x86"     if ARCH_x86
    default "x86_64"  if ARCH_x86_64

choice
    bool
    prompt "Target architecture:"
    default ARCH_x86

config ARCH_ARM
    bool
    prompt "arm"
    select ARCH_SUPPORTS_BOTH_ENDIAN
    select ARCH_DEFAULT_BE

config ARCH_MIPS
    bool
    prompt "mips"
    select ARCH_SUPPORTS_BOTH_ENDIAN
    select ARCH_DEFAULT_LE

config ARCH_x86
    bool
    prompt "x86"

config ARCH_x86_64
    bool
    prompt "x86_64"

endchoice

config ARCH_SUPPORTS_BOTH_ENDIAN
    bool
    default n

config ARCH_DEFAULT_BE
    bool
    default n

config ARCH_DEFAULT_LE
    bool
    default n

choice
    bool
    prompt "Endianness:"
    depends on ARCH_SUPPORTS_BOTH_ENDIAN
    default ARCH_BE if ARCH_DEFAULT_BE
    default ARCH_LE if ARCH_DEFAULT_LE

config ARCH_BE
    bool
    prompt "Big endian"

config ARCH_LE
    bool
    prompt "Little endian"

endchoice

comment "Target optimisations"

config ARCH_ARCH
    string
    prompt "Achitecture level"
    default ""
    help
      GCC uses this name to determine what kind of instructions it can emit
      when generating assembly code. This option can be used in conjunction
      with or instead of the ARCH_CPU option (above), or a (command-line)
      -mcpu= option.
      
      This is the configuration flag --with-arch=XXXX, and the runtime flag
      -march=XXX.
      
      Pick a value from the gcc manual for your choosen gcc version and your
      target CPU.
      
      Leave blank if you don't know, or if your target architecture does not
      offer this option.

config ARCH_ABI
    string
    prompt "Generate code for the specific ABI"
    default ""
    help
      Generate code for the given ABI.

      This is the configuration flag --with-abi=XXXX, and the runtime flag
      -mabi=XXX.

      Pick a value from the gcc manual for your choosen gcc version and your
      target CPU.

      Leave blank if you don't know, or if your target architecutre does not
      offer this option.

config ARCH_CPU
    string
    prompt "Emit assembly for CPU"
    default ""
    help
      This specifies the name of the target processor. GCC uses this name
      to determine what kind of instructions it can emit when generating
      assembly code.
      
      This is the configuration flag --with-cpu=XXXX, and the runtime flag
      -mcpu=XXX.

      Pick a value from the gcc manual for your choosen gcc version and your
      target CPU.
      
      Leave blank if you don't know, or if your target architecture does not
      offer this option.

config ARCH_TUNE
    string
    prompt "Tune for CPU"
    default ""
    help
      This option is very similar to the ARCH_CPU option (above), except
      that instead of specifying the actual target processor type, and hence
      restricting which instructions can be used, it specifies that GCC should
      tune the performance of the code as if the target were of the type
      specified in this option, but still choosing the instructions that it
      will generate based on the cpu specified by the ARCH_CPU option
      (above), or a (command-line) -mcpu= option.
      
      This is the configuration flag --with-tune=XXXX, and the runtime flag
      -mtune=XXX.
      
      Pick a value from the gcc manual for your choosen gcc version and your
      target CPU.
      
      Leave blank if you don't know, or if your target architecture does not
      offer this option.

config ARCH_FPU
    string
    prompt "Use specific FPU"
    default ""
    help
      On some targets (eg. ARM), you can specify the kind of FPU to emit
      code for.

      This is the configuration flag --with-fpu=XXX, and the runtime flag
      -mfpu=XXX.
      
      See below wether to actually emit FP opcodes, or to emulate them.
      
      Pick a value from the gcc manual for your choosen gcc version and your
      target CPU.
      
      Leave blank if you don't know, or if your target architecture does not
      offer this option.

choice
    bool
    prompt "Floating point:"

config ARCH_FLOAT_HW
    bool
    prompt "hardware (FPU)"
    help
      Emit hardware floating point opcodes.
      
      If you've got a processor with a FPU, then you want that.
      If your hardware has no FPU, you still can use HW floating point, but
      need to compile support for FPU emulation in your kernel. Needless to
      say that emulating the FPU is /slooowwwww/...
      
      One situation you'd want HW floating point without a FPU is if you get
      binary blobs from different vendors that are compiling this way and
      can't (don't wan't to) change.

config ARCH_FLOAT_SW
    bool
    prompt "software"
    help
      Do not emit any hardware floating point opcode.
      
      If your processor has no FPU, then you most probably want this, as it
      is faster than emulating the FPU in the kernel.

endchoice

config TARGET_CFLAGS
    string
    prompt "Target CFLAGS"
    default ""
    help
      Used to add specific options when compiling libraries of the toolchain,
      that will run on the target (eg. libc.so).
      
      Note that the options above for CPU, tune, arch and FPU will be
      automaticaly used. You don't need to specify them here.
      
      Leave blank if you don't know better.

endmenu