1 files changed, 83 insertions, 0 deletions
diff --git a/src/complex/cexpf.c b/src/complex/cexpf.c
new file mode 100644
index 00000000..0cf13a3d
--- /dev/null
+++ b/src/complex/cexpf.c
@@ -0,0 +1,83 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_cexpf.c */
+/*-
+ * Copyright (c) 2011 David Schultz <das@FreeBSD.ORG>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "libm.h"
+
+static const uint32_t
+exp_ovfl  = 0x42b17218,  /* MAX_EXP * ln2 ~= 88.722839355 */
+cexp_ovfl = 0x43400074;  /* (MAX_EXP - MIN_DENORM_EXP) * ln2 */
+
+float complex cexpf(float complex z)
+{
+	float x, y, exp_x;
+	uint32_t hx, hy;
+
+	x = crealf(z);
+	y = cimagf(z);
+
+	GET_FLOAT_WORD(hy, y);
+	hy &= 0x7fffffff;
+
+	/* cexp(x + I 0) = exp(x) + I 0 */
+	if (hy == 0)
+		return cpackf(expf(x), y);
+	GET_FLOAT_WORD(hx, x);
+	/* cexp(0 + I y) = cos(y) + I sin(y) */
+	if ((hx & 0x7fffffff) == 0)
+		return cpackf(cosf(y), sinf(y));
+
+	if (hy >= 0x7f800000) {
+		if ((hx & 0x7fffffff) != 0x7f800000) {
+			/* cexp(finite|NaN +- I Inf|NaN) = NaN + I NaN */
+			return cpackf(y - y, y - y);
+		} else if (hx & 0x80000000) {
+			/* cexp(-Inf +- I Inf|NaN) = 0 + I 0 */
+			return cpackf(0.0, 0.0);
+		} else {
+			/* cexp(+Inf +- I Inf|NaN) = Inf + I NaN */
+			return cpackf(x, y - y);
+		}
+	}
+
+	if (hx >= exp_ovfl && hx <= cexp_ovfl) {
+		/*
+		 * x is between 88.7 and 192, so we must scale to avoid
+		 * overflow in expf(x).
+		 */
+		return __ldexp_cexpf(z, 0);
+	} else {
+		/*
+		 * Cases covered here:
+		 *  -  x < exp_ovfl and exp(x) won't overflow (common case)
+		 *  -  x > cexp_ovfl, so exp(x) * s overflows for all s > 0
+		 *  -  x = +-Inf (generated by exp())
+		 *  -  x = NaN (spurious inexact exception from y)
+		 */
+		exp_x = expf(x);
+		return cpackf(exp_x * cosf(y), exp_x * sinf(y));
+	}
+}