freebsd-dev/contrib/libf2c/libF77/pow_qq.c
1999-09-18 10:51:31 +00:00

34 lines
449 B
C

#include "f2c.h"
#ifdef KR_headers
longint pow_qq(ap, bp) longint *ap, *bp;
#else
longint pow_qq(longint *ap, longint *bp)
#endif
{
longint pow, x, n;
unsigned long long u; /* system-dependent */
x = *ap;
n = *bp;
if (n <= 0) {
if (n == 0 || x == 1)
return 1;
if (x != -1)
return x == 0 ? 1/x : 0;
n = -n;
}
u = n;
for(pow = 1; ; )
{
if(u & 01)
pow *= x;
if(u >>= 1)
x *= x;
else
break;
}
return(pow);
}