diff options
Diffstat (limited to 'lib/libc/quad/floatdidf.c')
-rw-r--r-- | lib/libc/quad/floatdidf.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/lib/libc/quad/floatdidf.c b/lib/libc/quad/floatdidf.c new file mode 100644 index 0000000..7167715 --- /dev/null +++ b/lib/libc/quad/floatdidf.c @@ -0,0 +1,72 @@ +/*- + * Copyright (c) 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * This software was developed by the Computer Systems Engineering group + * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and + * contributed to Berkeley. + * + * 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. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)floatdidf.c 8.1 (Berkeley) 6/4/93"; +#endif /* LIBC_SCCS and not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "quad.h" + +/* + * Convert (signed) quad to double. + */ +double +__floatdidf(x) + quad_t x; +{ + double d; + union uu u; + int neg; + + /* + * Get an unsigned number first, by negating if necessary. + */ + if (x < 0) + u.q = -x, neg = 1; + else + u.q = x, neg = 0; + + /* + * Now u.ul[H] has the factor of 2^32 (or whatever) and u.ul[L] + * has the units. Ideally we could just set d, add LONG_BITS to + * its exponent, and then add the units, but this is portable + * code and does not know how to get at an exponent. Machine- + * specific code may be able to do this more efficiently. + */ + d = (double)u.ul[H] * ((1 << (LONG_BITS - 2)) * 4.0); + d += u.ul[L]; + + return (neg ? -d : d); +} |