sdcc/device/lib/_ulong2fs.c

   1 /*-------------------------------------------------------------------------
   2    _ulong2fs.c - Floating point library in optimized assembly for 8051
   3
   4    Copyright (c) 2004, Paul Stoffregen, paul@pjrc.com
   5
   6    This library is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 2, or (at your option) any
   9    later version.
  10
  11    This library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this library; see the file COPYING. If not, write to the
  18    Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  19    MA 02110-1301, USA.
  20
  21    As a special exception, if you link this library with other files,
  22    some of which are compiled with SDCC, to produce an executable,
  23    this library does not by itself cause the resulting executable to
  24    be covered by the GNU General Public License. This exception does
  25    not however invalidate any other reasons why the executable file
  26    might be covered by the GNU General Public License.
  27 -------------------------------------------------------------------------*/
  28
  29
  30 #define __SDCC_FLOAT_LIB
  31 #include <float.h>
  32
  33
  34 #ifdef FLOAT_ASM_MCS51
  35
  36 // float long __ulong2fs (float x)
  37 static void dummy(void) __naked
  38 {
  39         __asm
  40         .globl  ___ulong2fs
  41 ___ulong2fs:
  42         mov     r4, a
  43         mov     r3, b
  44         mov     r2, dph
  45         mov     r1, dpl
  46         mov     a, #158
  47         .globl  ulong2fs_doit
  48 ulong2fs_doit:
  49         clr     sign_a
  50 long2fs_doit:
  51         mov     exp_a, a
  52         lcall   fs_normalize_a
  53         ljmp    fs_round_and_return
  54         __endasm;
  55 }
  56
  57 #else
  58
  59 /*
  60 ** libgcc support for software floating point.
  61 ** Copyright (C) 1991 by Pipeline Associates, Inc.  All rights reserved.
  62 ** Permission is granted to do *anything* you want with this file,
  63 ** commercial or otherwise, provided this message remains intact.  So there!
  64 ** I would appreciate receiving any updates/patches/changes that anyone
  65 ** makes, and am willing to be the repository for said changes (am I
  66 ** making a big mistake?).
  67 **
  68 ** Pat Wood
  69 ** Pipeline Associates, Inc.
  70 ** pipeline!phw@motown.com or
  71 ** sun!pipeline!phw or
  72 ** uunet!motown!pipeline!phw
  73 */
  74
  75 /* (c)2000/2001: hacked a little by johan.knol@iduna.nl for sdcc */
  76 /* (c)2022:      fix sdcc bug #3276 -- Benedikt Freisen */
  77
  78 union float_long
  79   {
  80     float f;
  81     long l;
  82   };
  83
  84 float __ulong2fs (unsigned long a ) __SDCC_FLOAT_NONBANKED
  85 {
  86   unsigned char exp = (unsigned char)24 + (unsigned char)EXCESS;
  87   volatile union float_long fl;
  88
  89   if (!a)
  90     {
  91       return 0.0;
  92     }
  93
  94   if (a == 0xfffffffful)
  95     {
  96       return 4294967296.0f;
  97     }
  98
  99   while (a < HIDDEN)
 100     {
 101       a <<= 1;
 102       exp--;
 103     }
 104
 105   while (a & NORM)
 106     {
 107       // we lose accuracy here
 108       if (a & 1)
 109         a += 2;
 110       a >>= 1;
 111       exp++;
 112     }
 113
 114   a &= ~HIDDEN ;
 115   /* pack up and go home */
 116   fl.l = PACK(0,(unsigned long)exp, a);
 117
 118   return (fl.f);
 119 }
 120
 121 #endif