Quick question, does this have any relation to mips prefetching support?

I currently have to add /"# UCLIBC_USE_MIPS_PREFETCH is not set"/ to my uCling-ng.config for things to work. Is this option still needed for those that previously found it necessary given this new patch?

Lance Fredrickson

On 7/5/2019 6:49 AM, Waldemar Brodkorb wrote:

Hi,

patch applied and pushed, Waldemar

Petar Jovanovic wrote,

...

Hi All,

The previous patch to fix generic memmove() was incorrect even though it fixed issues with the tests. The comments in the memmove() function and different failing test cases misled me to believe the call to memcopy() was wrongly conditioned by __ARCH_HAS_BWD_MEMCPY__. It was not.

This generic memmove implementation assumes that memcpy does forward copying and that no issues could be seen in this case. However, at least MIPS arch has an optimized memcpy that uses prefetching and that implementation does not work correctly for overlapping regions.

So, my suggestions is that for now we skip memcpy() calls for MIPS, and if more arches in future come across this, we can unify it (same as it was done for __ARCH_HAS_BWD_MEMCPY__).

Sorry for not fixing this correctly in the first patch already.

Thanks.

Regards, Petar

Petar Jovanovic (1): mips: avoid calling memcpy() from memmove() for MIPS arch

libc/string/generic/memmove.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)

-- 2.17.1

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