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# Target definition: architecture, optimisations, etc...
menu "Target options"
config ARCH
string
# Pre-declare target optimisation variables
config ARCH_SUPPORT_ARCH
config ARCH_SUPPORT_ABI
config ARCH_SUPPORT_CPU
config ARCH_SUPPORT_TUNE
config ARCH_SUPPORT_FPU
config ARCH_SUPPORTS_BOTH_ENDIAN
config ARCH_DEFAULT_BE
config ARCH_DEFAULT_LE
config ARCH_ARCH
config ARCH_ABI
config ARCH_CPU
config ARCH_TUNE
config ARCH_FPU
config ARCH_BE
config ARCH_LE
config ARCH_FLOAT_HW
config ARCH_FLOAT_SW
config TARGET_CFLAGS
config TARGET_LDFLAGS
comment "General target options"
choice
bool
prompt "Target architecture:"
source config.gen/arch.in
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_SUPPORT_ARCH
bool
default n
config ARCH_SUPPORT_ABI
bool
default n
config ARCH_SUPPORT_CPU
bool
default n
config ARCH_SUPPORT_TUNE
bool
default n
config ARCH_SUPPORT_FPU
bool
default n
config ARCH_ARCH
string
prompt "Architecture level"
depends on ARCH_SUPPORT_ARCH
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_SUPPORT_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"
depends on ARCH_SUPPORT_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_SUPPORT_TUNE
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_SUPPORT_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 ARCH, ABI, CPU, TUNE and FPU will be
automaticaly 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.
endmenu
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