# Target definition: architecture, optimisations, etc... menu "Target options" config ARCH string # Pre-declare target optimisation variables config ARCH_SUPPORTS_BOTH_MMU config ARCH_SUPPORTS_BOTH_ENDIAN config ARCH_SUPPORTS_8 config ARCH_SUPPORTS_32 config ARCH_SUPPORTS_64 config ARCH_SUPPORTS_WITH_ARCH config ARCH_SUPPORTS_WITH_ABI config ARCH_SUPPORTS_WITH_CPU config ARCH_SUPPORTS_WITH_TUNE config ARCH_SUPPORTS_WITH_FLOAT config ARCH_SUPPORTS_WITH_FPU config ARCH_SUPPORTS_SOFTFP config ARCH_DEFAULT_HAS_MMU config ARCH_DEFAULT_BE config ARCH_DEFAULT_LE config ARCH_DEFAULT_32 config ARCH_DEFAULT_64 config ARCH_ARCH config ARCH_ABI config ARCH_CPU config ARCH_TUNE config ARCH_FPU config ARCH_BE config ARCH_LE config ARCH_32 config ARCH_64 config ARCH_BITNESS config ARCH_FLOAT_HW config ARCH_FLOAT_SW config TARGET_CFLAGS config TARGET_LDFLAGS source "config.gen/arch.in" config ARCH_SUFFIX string prompt "Suffix to the arch-part" help Some architectures have multiple variants and being able to specify the variant instead of the arch is quite convenient. This is commonly seen for instance when "armv5tel-" is used as a prefix instead of the more generic "arm-", or with "alphaev6-" instead of "alpha-". Whatever you enter here will be appended to the architecture-part of the tuple, just before the first '-'. It will override any architecture- specific suffix that crosstool-NG may compute. If you are not sure about what this is, leave it blank. #-------------------------------------- comment "Generic target options" #-------------------------------------- config ARCH_REQUIRES_MULTILIB bool select MULTILIB config MULTILIB bool prompt "Build a multilib toolchain (READ HELP!!!)" help If you say 'y' here, then the toolchain will also contain the C library optimised for some variants of the selected architecture, besides the default settings. This means the build time of the C library will be in O(nb_variants). The list of variants is dependent on the architecture, and is hard-coded in gcc, so it is not possible to say what variants to support, only whether hard-coded variants should be supported or not. NOTE: The multilib feature in crosstool-NG is not well-tested. Use at your own risk, and report success and/or failure. #-------------------------------------- config ARCH_SUPPORTS_BOTH_MMU bool config ARCH_DEFAULT_HAS_MMU bool config ARCH_USE_MMU bool prompt "Use the MMU" if ARCH_SUPPORTS_BOTH_MMU default y if ARCH_DEFAULT_HAS_MMU help If your architecture has an MMU and you want to use it, say 'Y' here. OTOH, if you don't want to use the MMU, or your arch lacks an MMU, say 'N' here. Note that some architectures (eg. ARM) has variants that lacks an MMU (eg. ARM Cortex-M3), while other variants have one (eg. ARM Cortex-A8). #-------------------------------------- config ARCH_SUPPORTS_BOTH_ENDIAN bool config ARCH_DEFAULT_BE bool config ARCH_DEFAULT_LE bool 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 config ARCH_ENDIAN string depends on ARCH_SUPPORTS_BOTH_ENDIAN default "big" if ARCH_BE default "little" if ARCH_LE #-------------------------------------- config ARCH_SUPPORTS_8 bool config ARCH_SUPPORTS_32 bool config ARCH_SUPPORTS_64 bool config ARCH_DEFAULT_8 bool config ARCH_DEFAULT_32 bool config ARCH_DEFAULT_64 bool config ARCH_BITNESS int default "8" if ARCH_8 default "32" if ARCH_32 default "64" if ARCH_64 choice bool prompt "Bitness:" default ARCH_8 if ARCH_DEFAULT_8 default ARCH_32 if ARCH_DEFAULT_32 default ARCH_64 if ARCH_DEFAULT_64 config ARCH_8 bool prompt "8-bit" depends on ARCH_SUPPORTS_8 config ARCH_32 bool prompt "32-bit" depends on ARCH_SUPPORTS_32 config ARCH_64 bool prompt "64-bit" depends on ARCH_SUPPORTS_64 endchoice #-------------------------------------- comment "Target optimisations" config ARCH_SUPPORTS_WITH_ARCH bool config ARCH_SUPPORTS_WITH_ABI bool config ARCH_SUPPORTS_WITH_CPU bool config ARCH_SUPPORTS_WITH_TUNE bool config ARCH_SUPPORTS_WITH_FLOAT bool config ARCH_SUPPORTS_WITH_FPU bool config ARCH_SUPPORTS_SOFTFP bool config ARCH_ARCH string prompt "Architecture level" depends on ARCH_SUPPORTS_WITH_ARCH depends on ARCH_CPU = "" 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" depends on ARCH_SUPPORTS_WITH_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 architecture does not offer this option. config ARCH_CPU string prompt "Emit assembly for CPU" depends on ARCH_SUPPORTS_WITH_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" depends on ARCH_SUPPORTS_WITH_TUNE depends on ARCH_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" depends on ARCH_SUPPORTS_WITH_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:" depends on ARCH_SUPPORTS_WITH_FLOAT config ARCH_FLOAT_AUTO bool prompt "auto (let gcc decide)" help Instead of explicitly passing a float option, don't pass any float options and let gcc figure it out. For multilib configurations, this may help. 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_SOFTFP bool prompt "softfp (FPU)" depends on ARCH_SUPPORTS_SOFTFP help Emit hardware floating point opcodes but use the software floating point calling convention. Architectures such as ARM use different registers for passing floating point values depending on if they're in software mode or hardware mode. softfp emits FPU instructions but uses the software FP calling convention allowing softfp code to interoperate with legacy software only code. If in doubt, use 'software' or 'hardware' mode instead. config ARCH_FLOAT_SW bool prompt "software (no FPU)" 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 ARCH, ABI, CPU, TUNE and FPU will be automatically used. You don't need to specify them here. Leave blank if you don't know better. config TARGET_LDFLAGS string prompt "Target LDFLAGS" default "" help Used to add specific options when linking libraries of the toolchain, that will run on your target. Leave blank if you don't know better. config ARCH_FLOAT string default "" if ! ARCH_SUPPORTS_WITH_FLOAT default "auto" if ARCH_FLOAT_AUTO default "hard" if ARCH_FLOAT_HW default "soft" if ARCH_FLOAT_SW default "softfp" if ARCH_FLOAT_SOFTFP source "config.gen/arch.in.2" endmenu