workbench/libs/mathieeesingtrans/intern_ieeespld.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <libraries/mathieeesp.h>
   7 #include <aros/libcall.h>
   8 #include <proto/mathieeesingbas.h>
   9 #include <proto/mathieeesingtrans.h>
  10 #include <proto/exec.h>
  11 #include <exec/types.h>
  12 #include "mathieeesingtrans_intern.h"
  13
  14 LONG intern_IEEESPLd(ULONG fnum)
  15 {
  16     ULONG i = 0, Res = 0;
  17     ULONG Mask = 0;
  18
  19     if (onehalf == fnum) return minusone;
  20
  21     while (Mask == 0 && i <= 23)
  22     {
  23         /* if (sqrtone < fnum) */
  24         if ( 0x00b504f3 < ((fnum & IEEESPMantisse_Mask) | 0x00800000) )
  25         {
  26             i++;
  27             fnum = IEEESPMul(fnum, fnum);
  28         }
  29         else
  30         {
  31             Mask = 0x40000000;
  32             fnum = IEEESPMul(fnum, fnum);
  33             fnum+= 0x00800000;
  34         }
  35     }
  36
  37     while ((char) Mask != 0x40)
  38     {
  39         if ( 0x00b504f3 < ((fnum & IEEESPMantisse_Mask) | 0x00800000) )
  40         {
  41             fnum = IEEESPMul(fnum, fnum);
  42         }
  43         else
  44         {
  45             Res |= Mask;
  46             fnum = IEEESPMul(fnum, fnum);
  47             fnum+= 0x00800000;
  48         }
  49         Mask >>= 1;
  50     }
  51
  52     /* for precision */
  53     if ((char) Res < 0) Res += 0x100;
  54
  55     Res >>= 8;
  56
  57     return (Res | ( (0x7e - i) << 23 ) | IEEESPSign_Mask );
  58 } /* intern_SPLd  */