2010/11/26 Marc Glisse <marc.glisse@xxxxxxxx>: > On Fri, 26 Nov 2010, Elias Gabriel Amaral da Silva wrote: > >> Seems to yield the same precision for long double on both ia32 and >> amd64 - that is, just 20 digits. This seems too few, looking there: >> >> http://en.wikipedia.org/wiki/IEEE_754-2008#Basic_formats >> >> Shouldn't I expect at least more than 30 digits, on amd64? > > long double would be binary80. > >> What is the trick for having 1/7 (or something else) with a precision >> closer to double's 52 digits? > > You seem to be confusing binary digits with decimal digits. Oh, you are right. 20 decimal digits seems to be roughly equivalent to 64 binary digits (20 * log10/log2 is ~66) one would encounter with 80-bits float. http://en.wikipedia.org/wiki/Extended_precision Thank you for your reply :) I'm cc-ing the one that firstly raised this question too
