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

Matteo Croce mcroce at linux.microsoft.com
Thu Jun 24 18:01:57 PDT 2021


From: Matteo Croce <mcroce at microsoft.com>

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@linux.microsoft.com/

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




More information about the linux-riscv mailing list