1 files changed, 35 insertions, 0 deletions
diff --git a/gnu/lib/libf2c/libF77/c_sqrt.c b/gnu/lib/libf2c/libF77/c_sqrt.c
new file mode 100644
index 00000000000..8481ee4857e
--- /dev/null
+++ b/gnu/lib/libf2c/libF77/c_sqrt.c
@@ -0,0 +1,35 @@
+#include "f2c.h"
+
+#ifdef KR_headers
+extern double sqrt(), f__cabs();
+
+VOID c_sqrt(r, z) complex *r, *z;
+#else
+#undef abs
+#include "math.h"
+extern double f__cabs(double, double);
+
+void c_sqrt(complex *r, complex *z)
+#endif
+{
+	double mag, t;
+	double zi = z->i, zr = z->r;
+
+	if( (mag = f__cabs(zr, zi)) == 0.)
+		r->r = r->i = 0.;
+	else if(zr > 0)
+		{
+		r->r = t = sqrt(0.5 * (mag + zr) );
+		t = zi / t;
+		r->i = 0.5 * t;
+		}
+	else
+		{
+		t = sqrt(0.5 * (mag - zr) );
+		if(zi < 0)
+			t = -t;
+		r->i = t;
+		t = zi / t;
+		r->r = 0.5 * t;
+		}
+	}