[src/trunk]: src/lib/libc/gen Provide a simple floatunditf implementation, at...

[joerg <joerg%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/fb34d3751f86
branches:  trunk
changeset: 326471:fb34d3751f86
user:      joerg <joerg%NetBSD.org@localhost>
date:      Thu Jan 30 15:06:18 2014 +0000

description:
Provide a simple floatunditf implementation, at least mips64 needs one.

diffstat:

 lib/libc/gen/floatunditf_ieee754.c |  81 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 81 insertions(+), 0 deletions(-)

diffs (85 lines):

diff -r c0a7edf7dad4 -r fb34d3751f86 lib/libc/gen/floatunditf_ieee754.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/libc/gen/floatunditf_ieee754.c        Thu Jan 30 15:06:18 2014 +0000
@@ -0,0 +1,81 @@
+/*     $NetBSD: floatunditf_ieee754.c,v 1.1 2014/01/30 15:06:18 joerg Exp $    */
+
+/*-
+ * Copyright (c) 2014 Joerg Sonnenberger <joerg%NetBSD.org@localhost>.
+ * 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 COPYRIGHT HOLDERS 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
+ * COPYRIGHT HOLDERS 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 <sys/cdefs.h>
+__RCSID("$NetBSD: floatunditf_ieee754.c,v 1.1 2014/01/30 15:06:18 joerg Exp $");
+
+#include <math.h>
+#include <machine/ieee.h>
+#include <limits.h>
+
+#ifdef __HAVE_LONG_DOUBLE
+
+long double __floatunditf(uint64_t x);
+
+/*
+ * Convert uint64_t to long double.
+ */
+long double
+__floatunditf(uint64_t x)
+{
+       int exponent, zeros;
+       union ieee_ext_u ux;
+
+       /* Use the easier conversion routine for uint32_t if possible. */
+       if (x <= UINT32_MAX)
+               return (long double)(uint32_t)x;
+
+       zeros = __builtin_clzll(x);
+#ifdef LDBL_IMPLICIT_NBIT
+       exponent = 64 - zeros;
+       x <<= zeros + 1;
+#else
+       exponent = 63 - zeros;
+       x <<= zeros;
+#endif
+
+       ux.extu_exp = EXT_EXP_BIAS + exponent;
+       ux.extu_frach = (x >> (64 - EXT_FRACHBITS));
+       x <<= EXT_FRACHBITS;
+#ifdef EXT_FRACHMBITS
+       ux.extu_frachm = (x >> (64 - EXT_FRACHMBITS));
+       x <<= EXT_FRACHMBITS;
+#endif
+#ifdef EXT_FRACLMBITS
+       ux.extu_fraclm = (x >> (64 - EXT_FRACLMBITS));
+       x <<= EXT_FRACLMBITS;
+#endif
+       ux.extu_fracl = (x >> (64 - EXT_FRACLBITS));
+       ux.extu_sign = 0;
+
+       return ux.extu_ld;
+}
+#endif /* __HAVE_LONG_DOUBLE */