[Python-Dev] Floating-point implementations

["Martin v. Löwis"]

> Is anyone aware of any implementations that use other than 64-bit
> floating-point?

As I understand you are asking about Python implementations:
sure, the gmpy package supports arbitrary-precision floating point.

> I'd be particularly interested in any that use greater
> precision than the usual 56-bit mantissa. 

Nit-pickingly: it's usual that the mantissa is 53-bit.

> Do modern 64-bit systems implement anything wider
> than the normal double?

As Mark said: sure. x86 systems have supported 80-bit
"extended" precision for ages. Some architectures have
architecture support for 128-bit floats (e.g. Itanium, SPARC v9);
it's not clear to me whether they actually implement the
long double operations in hardware, or whether they trap
and get software-emulated.

Regards,
Martin