> On 26 May 2017, at 11:01, Antonino Ficarra via swift-users
> <swift-users@swift.org> wrote:
>
> - Why Swift continues to not support Float80 math functions?
> Example:
>
> print("\( log( Float( 1.0 ) ) )")
> print("\( log( Double( 1.0 ) ) )")
> // print("\( log( Float80( 1.0 ) ) )") // don’t compile and logl is
> unavailable
In this case, it's because 'log' only is defined for Float and Double:
log(Double) -> Double
log(x: Double) -> Double
log(x: Float) -> Float
The problem is that Float80 types are represented in C as long double, and
currently the importer doesn't import things with long doubles. As a result,
logl doesn't get imported which is why it's not seen:
#include <math.h>
double
log(double x);
long double
logl(long double x);
The ones that do have Float80 support are done by hand, e.g.:
https://github.com/apple/swift/blob/19445cdb0e99eedf22390922e077d86f12123390/stdlib/public/SwiftShims/LibcShims.h#L138
The open bug is here, if you want to follow it:
https://bugs.swift.org/browse/SR-2046
>
> - Why min and max continue to not act like fmin and fmax (IEEE 754 standard)?
> Example:
>
> print("\( min( Double.nan,0.0 ) )") // print nan (!)
> print("\( min( 0.0,Double.nan ) )") // print 0.0
> print("\( max( Double.nan,0.0 ) )") // print nan (!)
> print("\( max( 0.0,Double.nan ) )") // print 0.0
> print("\n")
>
> print("\( fmin( Double.nan,0.0 ) )") // print 0.0
> print("\( fmin( 0.0,Double.nan ) )") // print 0.0
> print("\( fmax( Double.nan,0.0 ) )") // print 0.0
> print("\( fmax( 0.0,Double.nan ) )") // print 0.0
There is another open bug here:
https://bugs.swift.org/browse/SR-1011 <https://bugs.swift.org/browse/SR-1011>
Can you add your observations to that?
Thanks,
Alex_______________________________________________
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