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Re: SRFI-77 with more than one flonum representation



Bradley Lucier wrote:
While
it is possible to perform IEEE-754 double precision arithmetic
correctly on the IA32 architecture by writing every intermediate
result to memory,


This is not sufficient to simulate double x double -> double operations---pre- and post-scalings, as well as setting the mantissa precision to 53 bits, are necessary to eliminate double rounding and to compute possible denormal results correctly.

Yes. However, storing to memory solves the problem of writing (in C):

  double x = some expresion;
  double y = an identical expression;

and then finding that x != y because one variable was spilled to memory and the other was held in a FPU register.

Regards,

Alan
--
Dr Alan Watson
Centro de Radioastronomía y Astrofísica
Universidad Astronómico Nacional de México