Alexander Belopolsky added the comment:
I wonder if it would make sense to rewrite float_divmod using the newer
POSIX/C99 remquo function. I believe it is designed to compute the exact value
of round(x/y), but getting floor instead should not be hard. Its behavior on
special values is fully specified.
>From the Linux man-page (I believe POSIX/C99 only guarantees 3 bits in quo):
NAME
remquo -- floating-point remainder and quotient function
SYNOPSIS
#include <math.h>
double
remquo(double x, double y, int *quo);
long double
remquol(long double x, long double y, int *quo);
float
remquof(float x, float y, int *quo);
DESCRIPTION
The remquo() functions compute the value r such that r = x - n*y, where n
is
the integer nearest the exact value of x/y.
If there are two integers closest to x/y, n shall be the even one. If r is
zero, it is given the same sign as x. This is the same value that is
returned by the remainder() function. remquo() also calculates the lower
seven bits of the integral quotient x/y, and gives that value the same sign
as x/y. It stores this signed value in the object pointed to by quo.
SPECIAL VALUES
remquo(x, y, quo) returns a NaN and raises the "invalid" floating-point
exception if x is infinite or y is 0.
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Python tracker <[email protected]>
<http://bugs.python.org/issue22198>
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