On Mon, Oct 09, 2017 at 10:39:47PM +0200, Juan Francisco Cantero Hurtado wrote:
> Marc Feeley (Gambit Scheme) has been helping me with a bug on Gambit on
> Loongson. Apparently the bug is on our side.
>
> I've created this little test based on his code:
>
> #include <stdio.h>
> #include <math.h>
>
> int main()
> {
> double x = 0.5;
> double y = 1074.0;
> printf("x=%.20g y=%.20g pow(x,y)=%.20g\n",x,y,pow(x,y));
> return 0;
> }
>
> On OpenBSD/amd64, Linux/amd64, Linux/aarch64 and Linux/mips64:
> x=0.5 y=1074 pow(x,y)=4.9406564584124654418e-324
>
> On OpenBSD/loongson:
> x=0.5 y=1074 pow(x,y)=-4.9406564584124654418e-324
>
> Is the negative result expected?
No, even though what you are computing is ridiculous :)
My first thought would on Loongson would be softfloat bug.
But I am not 100% sure it (still) uses softfloat.
