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+/* origin: FreeBSD /usr/src/lib/msun/src/s_modfl.c */
+/*-
+ * Copyright (c) 2007 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.
+ *
+ * Derived from s_modf.c, which has the following Copyright:
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double modfl(long double x, long double *iptr)
+{
+ return modf(x, iptr);
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+
+#if LDBL_MANL_SIZE > 32
+#define MASK ((uint64_t)-1)
+#else
+#define MASK ((uint32_t)-1)
+#endif
+/* Return the last n bits of a word, representing the fractional part. */
+#define GETFRAC(bits, n) ((bits) & ~(MASK << (n)))
+/* The number of fraction bits in manh, not counting the integer bit */
+#define HIBITS (LDBL_MANT_DIG - LDBL_MANL_SIZE)
+
+static const long double zero[] = { 0.0L, -0.0L };
+
+long double modfl(long double x, long double *iptr)
+{
+ union IEEEl2bits ux;
+ int e;
+
+ ux.e = x;
+ e = ux.bits.exp - LDBL_MAX_EXP + 1;
+ if (e < HIBITS) { /* Integer part is in manh. */
+ if (e < 0) { /* |x|<1 */
+ *iptr = zero[ux.bits.sign];
+ return x;
+ }
+ if ((GETFRAC(ux.bits.manh, HIBITS - 1 - e)|ux.bits.manl) == 0) {
+ /* x is an integer. */
+ *iptr = x;
+ return zero[ux.bits.sign];
+ }
+ /* Clear all but the top e+1 bits. */
+ ux.bits.manh >>= HIBITS - 1 - e;
+ ux.bits.manh <<= HIBITS - 1 - e;
+ ux.bits.manl = 0;
+ *iptr = ux.e;
+ return x - ux.e;
+ } else if (e >= LDBL_MANT_DIG - 1) { /* x has no fraction part. */
+ *iptr = x;
+ if (x != x) /* Handle NaNs. */
+ return x;
+ return zero[ux.bits.sign];
+ } else { /* Fraction part is in manl. */
+ if (GETFRAC(ux.bits.manl, LDBL_MANT_DIG - 1 - e) == 0) {
+ /* x is integral. */
+ *iptr = x;
+ return zero[ux.bits.sign];
+ }
+ /* Clear all but the top e+1 bits. */
+ ux.bits.manl >>= LDBL_MANT_DIG - 1 - e;
+ ux.bits.manl <<= LDBL_MANT_DIG - 1 - e;
+ *iptr = ux.e;
+ return x - ux.e;
+ }
+}
+#endif