generic-poky/meta/conf/machine/include/mips/README
Mark Hatle d328ae22b7 conf/machine/include: Cleanup MIPS tunings to match README
Cleanup the MIPS tunings to match the new tuning README file.  Also
add a MIPS specific README file to explain the MIPS specifical
architectural issues.

Finally correct the variant configurations within the tune-mips32.inc.

(From OE-Core rev: efbfa2ace3362393a20340af93e8dcab17a8619a)

Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
2012-04-04 17:17:54 +01:00

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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
TUNE_ARCH, the GNU canonical arch, is defined as:
mips${MIPSPKGSFX_BYTE}${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_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.