fixunsdfdi.c
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/* $OpenBSD: fixunsdfdi.c,v 1.7 2005/08/08 08:05:35 espie Exp $ */
/*-
* 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. 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.
*/
#include "quad.h"
#define ONE_FOURTH ((int) 1 << (INT_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(double x)
{
union uu t;
unsigned int tmp;
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) { /* XXX */
return (UQUAD_MAX);
}
#endif
/*
* Now we know that 0 <= x <= 18446744073709549568. The upper
* limit is one ulp less than 18446744073709551615 tested for above.
* Dividing this by 2^32 will *not* round irrespective of any
* rounding modes (except if the result is an IEEE denorm).
* Furthermore, the quotient will fit into a 32-bit integer.
*/
tmp = x / ONE;
t.ul[L] = (unsigned int) (x - tmp * ONE);
t.ul[H] = tmp;
return (t.uq);
}