workbench/libs/mathtrans/sptieee.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include "mathtrans_intern.h"
   7
   8 /*****************************************************************************
   9
  10     NAME */
  11
  12         AROS_LH1(float, SPTieee,
  13
  14 /*  SYNOPSIS */
  15         AROS_LHA(float, fnum, D0),
  16
  17 /*  LOCATION */
  18         struct Library *, MathTransBase, 17, MathTrans)
  19
  20 /*  FUNCTION
  21         Convert FFP number to single precision ieee number
  22
  23     INPUTS
  24
  25     RESULT
  26         IEEE Single Precision Floating Point
  27
  28         flags:
  29         zero     : result is zero
  30         negative : result is negative
  31         overflow : exponent of the ieee-number was out of range for ffp
  32
  33     BUGS
  34
  35     INTERNALS
  36
  37 *****************************************************************************/
  38 {
  39     AROS_LIBFUNC_INIT
  40
  41     LONG Res;
  42     LONG Exponent;
  43     if (0 == fnum)
  44     {
  45         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  46         return 0;
  47     }
  48
  49     Exponent = (fnum & FFPExponent_Mask) - 0x40 + 126;
  50
  51     Res = ( Exponent << (30-7) );
  52     Res |= (((ULONG)fnum & 0x7fffff00) >> 8);
  53
  54     if ((char) fnum < 0)
  55     {
  56         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  57         Res |= IEEESPSign_Mask;
  58     }
  59
  60     return Res;
  61
  62     AROS_LIBFUNC_EXIT
  63 }