workbench/libs/mathtrans/intern_spld.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6
   7 #include <libraries/mathffp.h>
   8 #include <aros/libcall.h>
   9 #include <proto/mathffp.h>
  10 #include <proto/mathtrans.h>
  11 #include <exec/types.h>
  12 #include "mathtrans_intern.h"
  13
  14 LONG intern_SPLd(ULONG fnum)
  15 {
  16     ULONG i = 0, Res = 0, c;
  17     ULONG Mask = 0x80000000;
  18
  19     if (onehalf == fnum) return minusone;
  20
  21     while (Res == 0 && i <= 23)
  22     {
  23         if ( sqrtonehalf < fnum)
  24         {
  25             i++;
  26             fnum = SPMul(fnum, fnum);
  27         }
  28         else
  29         {
  30             Res = Mask;
  31             Mask >>= 1;
  32             fnum = SPMul(fnum, fnum);
  33             fnum++;
  34         }
  35     }
  36
  37     c = i;
  38
  39     while ((char) Mask != 0x40 && c < 24 )
  40     {
  41         if ( sqrtonehalf < fnum )
  42         {
  43             fnum = SPMul(fnum, fnum);
  44         }
  45         else
  46         {
  47             Res |= Mask;
  48             fnum = SPMul(fnum, fnum);
  49             fnum++;
  50         }
  51         c++;
  52         Mask >>= 1;
  53     }
  54
  55     /* for precision */
  56     if ((char) Res < 0)
  57     {
  58         Res += 0x100;
  59         Res &= FFPMantisse_Mask;
  60     }
  61
  62     return (Res | (0x40-i) | FFPSign_Mask);
  63 } /* intern_SPLd  */