1 files changed, 61 insertions, 0 deletions
diff --git a/gcc/f/runtime/libF77/pow_zi.c b/gcc/f/runtime/libF77/pow_zi.c
new file mode 100644
index 00000000000..898ea6be917
--- /dev/null
+++ b/gcc/f/runtime/libF77/pow_zi.c
@@ -0,0 +1,61 @@
+#include "f2c.h"
+
+#ifdef KR_headers
+VOID pow_zi(resx, a, b) 	/* p = a**b  */
+ doublecomplex *resx, *a; integer *b;
+#else
+extern void z_div(doublecomplex*, doublecomplex*, doublecomplex*);
+void pow_zi(doublecomplex *resx, doublecomplex *a, integer *b) 	/* p = a**b  */
+#endif
+{
+integer n;
+unsigned long u;
+double t;
+doublecomplex x;
+doublecomplex res;
+static doublecomplex one = {1.0, 0.0};
+
+n = *b;
+
+if(n == 0)
+	{
+	resx->r = 1;
+	resx->i = 0;
+	return;
+	}
+
+res.r = 1;
+res.i = 0;
+
+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 = res.r * x.r - res.i * x.i;
+		res.i = res.r * x.i + res.i * x.r;
+		res.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;
+	}
+
+resx->r = res.r;
+resx->i = res.i;
+}