freebsd-dev/lib/libF77/pow_qq.c

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#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);
}