[PATCH 0/3] lib/string: optimized mem* functions

From: Matteo Croce
Date: Thu Jun 24 2021 - 21:02:16 EST


From: Matteo Croce <mcroce@xxxxxxxxxxxxx>

Rewrite the generic mem{cpy,move,set} so that memory is accessed with
the widest size possible, but without doing unaligned accesses.

This was originally posted as C string functions for RISC-V[1], but as
there was no specific RISC-V code, it was proposed for the generic
lib/string.c implementation.

Tested on RISC-V and on x86_64 by undefining __HAVE_ARCH_MEM{CPY,SET,MOVE}
and HAVE_EFFICIENT_UNALIGNED_ACCESS.

Further testing on big endian machines will be appreciated, as I don't
have such hardware at the moment.

[1] https://lore.kernel.org/linux-riscv/20210617152754.17960-1-mcroce@xxxxxxxxxxxxxxxxxxx/

Matteo Croce (3):
lib/string: optimized memcpy
lib/string: optimized memmove
lib/string: optimized memset

lib/string.c | 129 ++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 112 insertions(+), 17 deletions(-)

--
2.31.1