mirror of
git://gcc.gnu.org/git/gcc.git
synced 2024-12-19 04:08:59 +08:00
55 lines
784 B
C
55 lines
784 B
C
#include "f2c.h"
|
|
|
|
#ifdef KR_headers
|
|
VOID pow_zi(p, a, b) /* p = a**b */
|
|
doublecomplex *p, *a; integer *b;
|
|
#else
|
|
extern void z_div(doublecomplex*, doublecomplex*, doublecomplex*);
|
|
void pow_zi(doublecomplex *p, doublecomplex *a, integer *b) /* p = a**b */
|
|
#endif
|
|
{
|
|
integer n;
|
|
unsigned long u;
|
|
double t;
|
|
doublecomplex q, x;
|
|
static doublecomplex one = {1.0, 0.0};
|
|
|
|
n = *b;
|
|
q.r = 1;
|
|
q.i = 0;
|
|
|
|
if(n == 0)
|
|
goto done;
|
|
if(n < 0)
|
|
{
|
|
n = -n;
|
|
z_div(&x, &one, a);
|
|
}
|
|
else
|
|
{
|
|
x.r = a->r;
|
|
x.i = a->i;
|
|
}
|
|
|
|
for(u = n; ; )
|
|
{
|
|
if(u & 01)
|
|
{
|
|
t = q.r * x.r - q.i * x.i;
|
|
q.i = q.r * x.i + q.i * x.r;
|
|
q.r = t;
|
|
}
|
|
if(u >>= 1)
|
|
{
|
|
t = x.r * x.r - x.i * x.i;
|
|
x.i = 2 * x.r * x.i;
|
|
x.r = t;
|
|
}
|
|
else
|
|
break;
|
|
}
|
|
done:
|
|
p->i = q.i;
|
|
p->r = q.r;
|
|
}
|