workbench/libs/mathieeedoubtrans/ieeedpfieee.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include "mathieeedoubtrans_intern.h"
   7
   8 /*
   9     FUNCTION
  10         Convert IEEE single to IEEE double precision
  11
  12     RESULT
  13         IEEE double precision floting point number
  14
  15         Flags:
  16           zero     : result is zero
  17           negative : result is negative
  18           overflow : 0
  19
  20     NOTES
  21
  22     EXAMPLE
  23
  24     BUGS
  25
  26     SEE ALSO
  27
  28     INTERNALS
  29
  30     HISTORY
  31 */
  32
  33 AROS_LHQUAD1(double, IEEEDPFieee,
  34     AROS_LHAQUAD(LONG, y, D0, D1),
  35     struct MathIeeeDoubTransBase *, MathIeeeDoubTransBase, 18, MathIeeeDoubTrans
  36 )
  37 {
  38     AROS_LIBFUNC_INIT
  39
  40     LONG tmpL = y & IEEESPExponent_Mask; /* get the Exponent */
  41     QUAD Res, tmpQ;
  42
  43     SetSR( 0, Zero_Bit | Overflow_Bit | Negative_Bit);
  44
  45     if (0 == y)
  46     {
  47         SetSR( Zero_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  48         Set_Value64C(Res, 0x0, 0x0);
  49         return Res;
  50     }
  51
  52     tmpL >>= 23;
  53     tmpL = tmpL - 0x7e + 0x3fe;
  54
  55     /* set the Exponent */
  56     SHL32(Res, tmpL, 52);
  57
  58     /* set the Mantisse */
  59     tmpL = y & IEEESPMantisse_Mask;
  60     SHL32(tmpQ, tmpL, 29);
  61     OR64Q(Res, tmpQ);
  62
  63     if (y < 0)
  64     {
  65         OR64QC(Res,  IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo);
  66         SetSR( Negative_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  67     }
  68
  69     return Res;
  70
  71     AROS_LIBFUNC_EXIT
  72 }