citadel/poky/meta/conf/machine/include/mips/README

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2016/09/30 - Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
- Add Release 6 support
2012/03/30 - Mark Hatle <mark.hatle@windriver.com>
- Initial Version
MIPS currently defines 12 ABIs. Combinations of:
*) Big/Little Endian
*) Hardware/Software Floating Point
*) o32, n32, n64 ABI
Release 6 of the ISA is a major revision and doesn't build up on previous
releases of the ISA.
For more details about tuples, check https://wiki.debian.org/Multiarch/Tuples
TUNE_ARCH, the GNU canonical arch, is defined as:
"mips${MIPSPKGSFX_32R6}${MIPSPKGSFX_64R6}${MIPSPKGSFX_BYTE}${MIPSPKGSFX_R6}${MIPSPKGSFX_ENDIAN}"
The package arch is defined in such a way to generated a standard naming
scheme. The scheme is: <mips variant>[-nf][-n32]
TUNE_PKGARCH is defined as:
${MIPSPKGSFX_VARIANT_tune-${DEFAULTTUNE}}${MIPSPKGSFX_FPU}${MIPSPKGSFX_ABI}
The following is a list of MIPS specific variables:
MIPSPKGSFX_BYTE - This is defined as either blank and "64" for MIPS64 CPUs.
MIPSPKGSFX_ENDIAN - For bigendian hardware this is blank, otherwise it's
defined as "el".
MIPSPKGSFX_ENDIAN2 - For bigendian hardware this is "eb", otherwise it's
defined as "el".
MIPSPKGSFX_VARIANT_tune-<tune> - In the default tunings it is set to the
same value as TUNE_ARCH. In custom, optimized tunings, the value should
be modified to more precisely describe the tuning.
MIPSPKGSFX_FPU - The value is set to "" or "-nf", where "-nf" indicates
that the tune is using a non-floating point ABI.
MIPSPKGSFX_ABI - This is used to specify an alternative ABI when the previous
values are not enough to distringuish the package. "-n32" is added when
building for N32 ABI.
MIPSPKGSFX_R6 - This is used to specify the presence of release 6.
"r6" is added in the tuple for release 6 of the isa.
MIPSPKGSFX_64R6 - This is used to specify "isa" in the tuple.
Release 6 onwards we use "mipsisa64" instead of just "mips64".
MIPSPKGSFX_32R6 - This is used to specify "isa32" in the tuple.
Release 6 onwards we use "mipsisa32" instead of just "mips".