sdcc/device/lib/_ulonglong2fs.c

   1 /*-------------------------------------------------------------------------
   2    _ulonglong2fs.c - Floating point library in optimized assembly for 8051
   3
   4    Copyright (c) 2004, Paul Stoffregen, paul@pjrc.com
   5                  2022, Benedikt Freisen
   6
   7    This library is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by the
   9    Free Software Foundation; either version 2, or (at your option) any
  10    later version.
  11
  12    This library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this library; see the file COPYING. If not, write to the
  19    Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  20    MA 02110-1301, USA.
  21
  22    As a special exception, if you link this library with other files,
  23    some of which are compiled with SDCC, to produce an executable,
  24    this library does not by itself cause the resulting executable to
  25    be covered by the GNU General Public License. This exception does
  26    not however invalidate any other reasons why the executable file
  27    might be covered by the GNU General Public License.
  28 -------------------------------------------------------------------------*/
  29
  30
  31 #define __SDCC_FLOAT_LIB
  32 #include <float.h>
  33
  34
  35 /*
  36 ** libgcc support for software floating point.
  37 ** Copyright (C) 1991 by Pipeline Associates, Inc.  All rights reserved.
  38 ** Permission is granted to do *anything* you want with this file,
  39 ** commercial or otherwise, provided this message remains intact.  So there!
  40 ** I would appreciate receiving any updates/patches/changes that anyone
  41 ** makes, and am willing to be the repository for said changes (am I
  42 ** making a big mistake?).
  43 **
  44 ** Pat Wood
  45 ** Pipeline Associates, Inc.
  46 ** pipeline!phw@motown.com or
  47 ** sun!pipeline!phw or
  48 ** uunet!motown!pipeline!phw
  49 */
  50
  51 /* (c)2000/2001: hacked a little by johan.knol@iduna.nl for sdcc */
  52 /* (c)2022:      fix sdcc bug #3276 -- Benedikt Freisen */
  53 /*               ported from ulong to ulonglong -- Benedikt Freisen */
  54
  55 union float_long
  56   {
  57     float f;
  58     long l;
  59   };
  60
  61 float __ulonglong2fs (unsigned long long a ) __SDCC_FLOAT_NONBANKED
  62 {
  63   unsigned char exp = (unsigned char)24 + (unsigned char)EXCESS;
  64   volatile union float_long fl;
  65
  66   if (!a)
  67     {
  68       return 0.0;
  69     }
  70
  71   if (a == 0xffffffffffffffffull)
  72     {
  73       return 18446744073709551616.0f;
  74     }
  75
  76   while (a < HIDDEN)
  77     {
  78       a <<= 1;
  79       exp--;
  80     }
  81
  82   while (a & NORM)
  83     {
  84       // we lose accuracy here
  85       if (a & 1)
  86         a += 2;
  87       a >>= 1;
  88       exp++;
  89     }
  90
  91   a &= ~HIDDEN ;
  92   /* pack up and go home */
  93   fl.l = PACK(0,(unsigned long)exp, a);
  94
  95   return (fl.f);
  96 }