pow_qq.c

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#include "f2c.h"
#ifdef __cplusplus
extern "C" {
#endif

#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);
        }
#ifdef __cplusplus
}
#endif