aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/libf2c/pow_qq.c
blob: 09fe18ec8e75dd74f4f3e4f14617e85fe125bc62 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
#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