ack/lang/fortran/lib/libF77/pow_di.c

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1991-10-07 16:59:33 +00:00
#include "f2c.h"
double pow_di(ap, bp)
doublereal *ap;
integer *bp;
{
double pow, x;
integer n;
pow = 1;
x = *ap;
n = *bp;
if(n != 0)
{
if(n < 0)
{
if(x == 0)
{
return(pow);
}
n = -n;
x = 1/x;
}
for( ; ; )
{
if(n & 01)
pow *= x;
if(n >>= 1)
x *= x;
else
break;
}
}
return(pow);
}