lib/libc/gen/fixunsdfsi_ieee754.c

   1 /*      $NetBSD: fixunsdfsi_ieee754.c,v 1.3 2013/04/30 01:44:07 matt Exp $      */
   2 /*-
   3  * Copyright (c) 2011 The NetBSD Foundation, Inc.
   4  * All rights reserved.
   5  *
   6  * This code is derived from software contributed to The NetBSD Foundation
   7  * by Matt Thomas of 3am Software Foundry.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  20  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  22  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28  * POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 __RCSID("$NetBSD: fixunsdfsi_ieee754.c,v 1.3 2013/04/30 01:44:07 matt Exp $");
  35 #endif /* LIBC_SCCS and not lint */
  36
  37 #include <stdbool.h>
  38 #include <stdint.h>
  39 #include <float.h>
  40 #include <machine/ieee.h>
  41
  42 #if defined(SOFTFLOAT) || defined(__ARM_EABI__)
  43 #include "softfloat/softfloat-for-gcc.h"
  44 #endif
  45
  46 uint32_t __fixunsgen32(int, bool, size_t, size_t, const uint32_t *);
  47
  48 uint32_t __fixunsdfsi(double);
  49
  50 /*
  51  * Convert double to (unsigned) int.  All operations are done module 2^32.
  52  */
  53 uint32_t
  54 __fixunsdfsi(double x)
  55 {
  56         const union ieee_double_u dblu = { .dblu_d = x };
  57         const uint32_t frac[(DBL_FRACBITS + 31)/32 + 1] = {
  58                 [0] = 0,
  59                 [1] = dblu.dblu_dbl.dbl_fracl,
  60                 [2] = dblu.dblu_dbl.dbl_frach,
  61         };
  62
  63         return __fixunsgen32(
  64                 dblu.dblu_dbl.dbl_exp - DBL_EXP_BIAS,
  65                 dblu.dblu_dbl.dbl_sign != 0,
  66                 DBL_MANT_DIG,
  67                 DBL_FRACHBITS,
  68                 &frac[__arraycount(frac)-1]);
  69 }