[cfarm-announces] New Arm Morello SoC machine: cfarm240

Torbjörn Granlund tg at gmplib.org
Thu Aug 24 10:42:56 CEST 2023

Marc Glisse <marc.glisse at inria.fr> writes:

  Hmm, but with that proposed patch, configure later fails with

  checking size of void *... 16
  checking size of unsigned short... 2
  checking size of unsigned... 4
  checking size of unsigned long... 8
  checking size of mp_limb_t... 8
  configure: error: Oops, mp_limb_t is 64 bits, but the assembler code
  in this configuration expects 32 bits.

  configure --disable-assembly does allow to build the library, but then
  quite a few tests fail with "bus error": t-toom6h, t-toom8h,
  t-toom8-sqr, t-div, t-mulmod_bnm1, ..., t-sizeinbase.

  So more work is needed on the GMP side :-(

Note the size of pointers, 16 bytes.  There is no integer type mathing
that, so if code tries to cast a pointer through some integer type for,
say, aligning it, things will break.

Apparently, this is some sort of research platform.  I have no idea how
hard a GMP port might be,

I've given up trying to make GMP run well on Arm since it is too hard
and too expensive to find hardware for 90% of the Arm cores.  There are
lots of "Fruit Pi" boards, but they all use a small set of processor
cores (essentially A55, A72, and A73) or cost and arm (no pun intended)
and a leg.

But GMP at least runs on most Arm cores, as long as they follow the
standard ABI.

Please encrypt, key id 0xC8601622

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