Bug#724320: gmp: x32: sizeof(mp_limb_t)!=sizeof(void*) is not supported by GAP and PARI

Torbjorn Granlund tg at gmplib.org
Sat Sep 28 13:37:14 CEST 2013

[I trimmed 724320 at bugs.debian.org, the Debian policy of outing people's
private email addresses to spammers is intolerable.]

"Steve M. Robbins" <steve at sumost.ca> writes:

  For readers of gmp-discuss and Daniel Schepler: this concerns a bug reported 
  to Debian regarding GMP on the x32 architecture.  In a nutshell: x32 selects a 
  limb size of 8, which means it is larger than a pointer and some software 
  (gap, pari) fail to build.  The question is whether it makes sense to change
  the limb size to 4 on x32.  I'd appreciate your thoughts.
That does not make sense; we have ABI=32 which will do *exactly* that.
Software that expects sizeof(mp_limb_t) <= sizeof(pointer) needs to be

There is a host of GMP configurations where mp_limb_t is 64 bits but
pointers are just 32.  I suppose most of these configs are somewhat
obscure, and thus gap and pari have not been fixed to handle that.

(hppa2.0n, mips n32 are two examples I recall now.)


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