# 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 config ARCH_MIPS bool prompt "mips" select ARCH_SUPPORTS_BOTH_ENDIAN config ARCH_x86 bool prompt "x86" config ARCH_x86_64 bool prompt "x86_64" endchoice config ARCH_SUPPORTS_BOTH_ENDIAN bool default n choice bool prompt "Endianness:" depends on ARCH_SUPPORTS_BOTH_ENDIAN 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