NetCube-Systems-Austria/kumquat-buildroot
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Revert "configs/olimex_a20_olinuxino_lime: use NEON+VFPv4 as FPU strategy"

Browse Source 
The gcc man page states that specifying Neon as part of the fpu setting
has no effect, unless the -funsafe-math-optimizations is also specified,
because Neon is not compliant with IEEE 754:
```
    If the selected floating-point hardware includes the NEON extension
    (e.g. -mfpu=neon), note that floating-point operations are not
    generated by GCC's auto-vectorization pass unless
    -funsafe-math-optimizations is also specified. This is because NEON
    hardware does not fully implement the IEEE 754 standard for
    floating-point arithmetic (in particular denormal values are treated
    as zero), so the use of NEON instructions may lead to a loss of
    precision.
```

-funsafe-math-optimizations must be explictly specified per package to
really use NEON as FPU, but it's something that is left to the user as
well as setting BR2_ARM_FPU_NEON_VFPV4. This way the default
BR2_ARM_FPU_VFPV4D16 is used as previously. So let's revert the
offending patch.

This reverts commit 115ee05214.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
This commit is contained in:
Giulio Benetti 2022-08-15 17:48:53 +02:00 committed by Yann E. MORIN
parent 869fe1fbab
commit d5c1e67d3a
1 changed files with 0 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
configs/olimex_a20_olinuxino_lime_defconfig
View File

@ -2,7 +2,6 @@
BR2_arm=y
BR2_cortex_a7=y
BR2_ARM_EABIHF=y
BR2_ARM_FPU_NEON_VFPV4=y
# Linux headers same as kernel, a 5.15 LTS series
BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_15=y