[gambit-list] Numbers and R5RS section 6.2, SRFI-70

Bradley Lucier lucier at math.purdue.edu
Sat Dec 29 23:08:19 EST 2012


On Dec 29, 2012, at 10:04 PM, David Rush wrote:

> On 28 December 2012 16:53, Bradley Lucier <lucier at math.purdue.edu> wrote:
> Inexact numbers are the same as C doubles (64-bit).  Extended precision floating-point numbers (80-bit numbers) are used in extremis on machines that do not support 64-bit floating-point numbers natively.  (Don't ask.)
> 
> Too late. Besides i have a penchant for quirky/bizarre architectures. Are we talking about x86 here?

x86 without the SSE extension.  In which case the precision of the mantissa of operations is set to 53 bits, but the exponent range of operations is still the exponent range of extended reals.  But inexact numbers are still stored as doubles.

I don't remember all the details; most of the time, results are as expected, but not always---for subnormal numbers double rounding can sometimes occur, for example.

Brad
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.iro.umontreal.ca/pipermail/gambit-list/attachments/20121229/0f431edb/attachment.htm>


More information about the Gambit-list mailing list