1 files changed, 87 insertions, 0 deletions
diff --git a/src/math/rintl.c b/src/math/rintl.c
new file mode 100644
index 00000000..1cc35df5
--- /dev/null
+++ b/src/math/rintl.c
@@ -0,0 +1,87 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_rintl.c */
+/*-
+ * Copyright (c) 2008 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"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double rintl(long double x)
+{
+	return rint(x);
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+
+#define BIAS    (LDBL_MAX_EXP - 1)
+
+static const float
+shift[2] = {
+#if LDBL_MANT_DIG == 64
+	0x1.0p63, -0x1.0p63
+#elif LDBL_MANT_DIG == 113
+	0x1.0p112, -0x1.0p112
+#else
+#error "Unsupported long double format"
+#endif
+};
+static const float zero[2] = { 0.0, -0.0 };
+
+long double rintl(long double x)
+{
+	union IEEEl2bits u;
+	uint32_t expsign;
+	int ex, sign;
+
+	u.e = x;
+	expsign = u.xbits.expsign;
+	ex = expsign & 0x7fff;
+
+	if (ex >= BIAS + LDBL_MANT_DIG - 1) {
+		if (ex == BIAS + LDBL_MAX_EXP)
+			return x + x; /* Inf, NaN, or unsupported format */
+		return x;             /* finite and already an integer */
+	}
+	sign = expsign >> 15;
+
+	/*
+	 * The following code assumes that intermediate results are
+	 * evaluated in long double precision. If they are evaluated in
+	 * greater precision, double rounding may occur, and if they are
+	 * evaluated in less precision (as on i386), results will be
+	 * wildly incorrect.
+	 */
+	x += shift[sign];
+	x -= shift[sign];
+
+	/*
+	 * If the result is +-0, then it must have the same sign as x, but
+	 * the above calculation doesn't always give this.  Fix up the sign.
+	 */
+	if (ex < BIAS && x == 0.0L)
+		return zero[sign];
+
+	return x;
+}
+#endif