diff options
Diffstat (limited to 'lib/libc/quad/fixunsdfdi.c')
| -rw-r--r-- | lib/libc/quad/fixunsdfdi.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/lib/libc/quad/fixunsdfdi.c b/lib/libc/quad/fixunsdfdi.c new file mode 100644 index 0000000..601790f --- /dev/null +++ b/lib/libc/quad/fixunsdfdi.c @@ -0,0 +1,96 @@ +/*- + * 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. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 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[] = "@(#)fixunsdfdi.c 8.1 (Berkeley) 6/4/93"; +#endif /* LIBC_SCCS and not lint */ + +#include "quad.h" + +#define ONE_FOURTH (1 << (LONG_BITS - 2)) +#define ONE_HALF (ONE_FOURTH * 2.0) +#define ONE (ONE_FOURTH * 4.0) + +/* + * Convert double to (unsigned) quad. + * Not sure what to do with negative numbers---for now, anything out + * of range becomes UQUAD_MAX. + */ +u_quad_t +__fixunsdfdi(x) + double x; +{ + double toppart; + union uu t; + + if (x < 0) + return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ +#ifdef notdef /* this falls afoul of a GCC bug */ + if (x >= UQUAD_MAX) + return (UQUAD_MAX); +#else /* so we wire in 2^64-1 instead */ + if (x >= 18446744073709551615.0) + return (UQUAD_MAX); +#endif + /* + * Get the upper part of the result. Note that the divide + * may round up; we want to avoid this if possible, so we + * subtract `1/2' first. + */ + toppart = (x - ONE_HALF) / ONE; + /* + * Now build a u_quad_t out of the top part. The difference + * between x and this is the bottom part (this may introduce + * a few fuzzy bits, but what the heck). With any luck this + * difference will be nonnegative: x should wind up in the + * range [0..ULONG_MAX]. For paranoia, we assume [LONG_MIN.. + * 2*ULONG_MAX] instead. + */ + t.ul[H] = (unsigned long)toppart; + t.ul[L] = 0; + x -= (double)t.uq; + if (x < 0) { + t.ul[H]--; + x += ULONG_MAX; + } + if (x > ULONG_MAX) { + t.ul[H]++; + x -= ULONG_MAX; + } + t.ul[L] = (u_long)x; + return (t.uq); +} |
