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13fcbed86e
Add an ARCH_FLOAT_AUTO option to avoid passing float options to gcc and allow it to choose Signed-off-by: Cody P Schafer <dev@codyps.com> [yann.morin.1998@free.fr: slightly reword the commit log] Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr> Message-Id: <088489641f4790262685.1399687813@localhost> Patchwork-Id: 347584
384 lines
10 KiB
Plaintext
384 lines
10 KiB
Plaintext
# Target definition: architecture, optimisations, etc...
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menu "Target options"
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config ARCH
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string
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# Pre-declare target optimisation variables
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config ARCH_SUPPORTS_BOTH_MMU
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config ARCH_SUPPORTS_BOTH_ENDIAN
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config ARCH_SUPPORTS_32
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config ARCH_SUPPORTS_64
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config ARCH_SUPPORTS_WITH_ARCH
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config ARCH_SUPPORTS_WITH_ABI
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config ARCH_SUPPORTS_WITH_CPU
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config ARCH_SUPPORTS_WITH_TUNE
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config ARCH_SUPPORTS_WITH_FLOAT
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config ARCH_SUPPORTS_WITH_FPU
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config ARCH_SUPPORTS_SOFTFP
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config ARCH_DEFAULT_HAS_MMU
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config ARCH_DEFAULT_BE
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config ARCH_DEFAULT_LE
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config ARCH_DEFAULT_32
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config ARCH_DEFAULT_64
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config ARCH_ARCH
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config ARCH_ABI
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config ARCH_CPU
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config ARCH_TUNE
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config ARCH_FPU
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config ARCH_BE
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config ARCH_LE
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config ARCH_32
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config ARCH_64
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config ARCH_BITNESS
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config ARCH_FLOAT_HW
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config ARCH_FLOAT_SW
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config TARGET_CFLAGS
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config TARGET_LDFLAGS
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source "config.gen/arch.in"
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config ARCH_SUFFIX
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string
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prompt "Suffix to the arch-part"
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help
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Some architectures have multiple variants and being able to specify
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the variant instead of the arch is quite convenient. This is commonly
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seen for instance when "armv5tel-" is used as a prefix instead of the
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more generic "arm-", or with "alphaev6-" instead of "alpha-".
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Whatever you enter here will be appended to the architecture-part of the
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tuple, just before the first '-'. It will override any architecture-
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specific suffix that crosstool-NG may compute.
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If you are not sure about what this is, leave it blank.
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#--------------------------------------
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comment "Generic target options"
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#--------------------------------------
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config MULTILIB
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bool
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prompt "Build a multilib toolchain (READ HELP!!!)"
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help
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If you say 'y' here, then the toolchain will also contain the C library
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optimised for some variants of the selected architecture, besides the
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default settings.
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This means the build time of the C library will be in O(nb_variants).
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The list of variants is dependent on the architecture, and is hard-coded
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in gcc, so it is not possible to say what variants to support, only
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whether hard-coded variants should be supported or not.
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NOTE: The multilib feature in crosstool-NG is not well-tested.
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Use at your own risk, and report success and/or failure.
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#--------------------------------------
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config ARCH_SUPPORTS_BOTH_MMU
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bool
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config ARCH_DEFAULT_HAS_MMU
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bool
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config ARCH_USE_MMU
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bool
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prompt "Use the MMU" if ARCH_SUPPORTS_BOTH_MMU
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default y if ARCH_DEFAULT_HAS_MMU
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help
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If your architecture has an MMU and you want to use it,
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say 'Y' here.
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OTOH, if you don't want to use the MMU, or your arch
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lacks an MMU, say 'N' here.
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Note that some architectures (eg. ARM) has variants that
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lacks an MMU (eg. ARM Cortex-M3), while other variants
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have one (eg. ARM Cortex-A8).
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#--------------------------------------
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config ARCH_SUPPORTS_BOTH_ENDIAN
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bool
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config ARCH_DEFAULT_BE
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bool
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config ARCH_DEFAULT_LE
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bool
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choice
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bool
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prompt "Endianness:"
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depends on ARCH_SUPPORTS_BOTH_ENDIAN
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default ARCH_BE if ARCH_DEFAULT_BE
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default ARCH_LE if ARCH_DEFAULT_LE
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config ARCH_BE
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bool
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prompt "Big endian"
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config ARCH_LE
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bool
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prompt "Little endian"
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endchoice
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config ARCH_ENDIAN
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string
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depends on ARCH_SUPPORTS_BOTH_ENDIAN
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default "big" if ARCH_BE
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default "little" if ARCH_LE
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#--------------------------------------
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config ARCH_SUPPORTS_32
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bool
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config ARCH_SUPPORTS_64
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bool
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config ARCH_DEFAULT_32
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bool
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config ARCH_DEFAULT_64
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bool
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config ARCH_BITNESS
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int
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default "32" if ARCH_32
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default "64" if ARCH_64
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choice
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bool
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prompt "Bitness:"
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default ARCH_32 if ARCH_DEFAULT_32
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default ARCH_64 if ARCH_DEFAULT_64
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config ARCH_32
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bool
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prompt "32-bit"
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depends on ARCH_SUPPORTS_32
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config ARCH_64
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bool
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prompt "64-bit"
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depends on ARCH_SUPPORTS_64
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endchoice
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#--------------------------------------
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comment "Target optimisations"
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config ARCH_SUPPORTS_WITH_ARCH
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bool
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config ARCH_SUPPORTS_WITH_ABI
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bool
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config ARCH_SUPPORTS_WITH_CPU
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bool
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config ARCH_SUPPORTS_WITH_TUNE
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bool
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config ARCH_SUPPORTS_WITH_FLOAT
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bool
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config ARCH_SUPPORTS_WITH_FPU
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bool
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config ARCH_SUPPORTS_SOFTFP
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bool
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config ARCH_ARCH
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string
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prompt "Architecture level"
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depends on ARCH_SUPPORTS_WITH_ARCH
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default ""
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help
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GCC uses this name to determine what kind of instructions it can emit
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when generating assembly code. This option can be used in conjunction
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with or instead of the ARCH_CPU option (above), or a (command-line)
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-mcpu= option.
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This is the configuration flag --with-arch=XXXX, and the runtime flag
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-march=XXX.
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Pick a value from the gcc manual for your choosen gcc version and your
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target CPU.
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Leave blank if you don't know, or if your target architecture does not
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offer this option.
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config ARCH_ABI
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string
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prompt "Generate code for the specific ABI"
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depends on ARCH_SUPPORTS_WITH_ABI
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default ""
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help
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Generate code for the given ABI.
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This is the configuration flag --with-abi=XXXX, and the runtime flag
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-mabi=XXX.
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Pick a value from the gcc manual for your choosen gcc version and your
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target CPU.
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Leave blank if you don't know, or if your target architecture does not
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offer this option.
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config ARCH_CPU
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string
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prompt "Emit assembly for CPU"
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depends on ARCH_SUPPORTS_WITH_CPU
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default ""
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help
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This specifies the name of the target processor. GCC uses this name
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to determine what kind of instructions it can emit when generating
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assembly code.
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This is the configuration flag --with-cpu=XXXX, and the runtime flag
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-mcpu=XXX.
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Pick a value from the gcc manual for your choosen gcc version and your
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target CPU.
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Leave blank if you don't know, or if your target architecture does not
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offer this option.
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config ARCH_TUNE
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string
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prompt "Tune for CPU"
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depends on ARCH_SUPPORTS_WITH_TUNE
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default ""
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help
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This option is very similar to the ARCH_CPU option (above), except
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that instead of specifying the actual target processor type, and hence
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restricting which instructions can be used, it specifies that GCC should
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tune the performance of the code as if the target were of the type
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specified in this option, but still choosing the instructions that it
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will generate based on the cpu specified by the ARCH_CPU option
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(above), or a (command-line) -mcpu= option.
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This is the configuration flag --with-tune=XXXX, and the runtime flag
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-mtune=XXX.
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Pick a value from the gcc manual for your choosen gcc version and your
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target CPU.
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Leave blank if you don't know, or if your target architecture does not
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offer this option.
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config ARCH_FPU
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string
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prompt "Use specific FPU"
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depends on ARCH_SUPPORTS_WITH_FPU
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default ""
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help
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On some targets (eg. ARM), you can specify the kind of FPU to emit
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code for.
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This is the configuration flag --with-fpu=XXX, and the runtime flag
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-mfpu=XXX.
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See below wether to actually emit FP opcodes, or to emulate them.
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Pick a value from the gcc manual for your choosen gcc version and your
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target CPU.
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Leave blank if you don't know, or if your target architecture does not
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offer this option.
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choice
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bool
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prompt "Floating point:"
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depends on ARCH_SUPPORTS_WITH_FLOAT
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config ARCH_FLOAT_AUTO
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bool
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prompt "auto (let gcc decide)"
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help
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Instead of explicitly passing a float option, don't
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pass any float options and let gcc figure it out.
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For multilib configurations, this may help.
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config ARCH_FLOAT_HW
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bool
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prompt "hardware (FPU)"
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help
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Emit hardware floating point opcodes.
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If you've got a processor with a FPU, then you want that.
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If your hardware has no FPU, you still can use HW floating point, but
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need to compile support for FPU emulation in your kernel. Needless to
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say that emulating the FPU is /slooowwwww/...
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One situation you'd want HW floating point without a FPU is if you get
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binary blobs from different vendors that are compiling this way and
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can't (don't wan't to) change.
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config ARCH_FLOAT_SOFTFP
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bool
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prompt "softfp (FPU)"
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depends on ARCH_SUPPORTS_SOFTFP
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help
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Emit hardware floating point opcodes but use the software
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floating point calling convention.
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Architectures such as ARM use different registers for passing
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floating point values depending on if they're in software mode
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or hardware mode. softfp emits FPU instructions but uses the
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software FP calling convention allowing softfp code to
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interoperate with legacy software only code.
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If in doubt, use 'software' or 'hardware' mode instead.
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config ARCH_FLOAT_SW
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bool
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prompt "software (no FPU)"
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help
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Do not emit any hardware floating point opcode.
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If your processor has no FPU, then you most probably want this, as it
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is faster than emulating the FPU in the kernel.
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endchoice
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config TARGET_CFLAGS
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string
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prompt "Target CFLAGS"
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default ""
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help
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Used to add specific options when compiling libraries of the toolchain,
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that will run on the target (eg. libc.so).
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Note that the options above for ARCH, ABI, CPU, TUNE and FPU will be
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automatically used. You don't need to specify them here.
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Leave blank if you don't know better.
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config TARGET_LDFLAGS
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string
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prompt "Target LDFLAGS"
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default ""
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help
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Used to add specific options when linking libraries of the toolchain,
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that will run on your target.
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Leave blank if you don't know better.
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config ARCH_FLOAT
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string
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default "" if ! ARCH_SUPPORTS_WITH_FLOAT
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default "auto" if ARCH_FLOAT_AUTO
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default "hard" if ARCH_FLOAT_HW
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default "soft" if ARCH_FLOAT_SW
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default "softfp" if ARCH_FLOAT_SOFTFP
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source "config.gen/arch.in.2"
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endmenu
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