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
  10     NAME */
  11
  12         AROS_LH1(double, IEEEDPFieee,
  13
  14 /*  SYNOPSIS */
  15         AROS_LHA(LONG, y, D0),
  16
  17 /*  LOCATION */
  18         struct MathIeeeDoubTransBase *, MathIeeeDoubTransBase, 18, MathIeeeDoubTrans)
  19
  20 /*  FUNCTION
  21         Convert IEEE single to IEEE double precision
  22
  23     INPUTS
  24
  25     RESULT
  26         IEEE double precision floting point number
  27
  28         Flags:
  29           zero     : result is zero
  30           negative : result is negative
  31           overflow : 0
  32
  33     BUGS
  34
  35     INTERNALS
  36
  37 *****************************************************************************/
  38 {
  39     AROS_LIBFUNC_INIT
  40
  41     LONG tmpL = y & IEEESPExponent_Mask; /* get the Exponent */
  42     QUAD Res, tmpQ;
  43
  44     SetSR( 0, Zero_Bit | Overflow_Bit | Negative_Bit);
  45
  46     if (0 == y)
  47     {
  48         SetSR( Zero_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  49         Set_Value64C(Res, 0x0, 0x0);
  50         return Res;
  51     }
  52
  53     tmpL >>= 23;
  54     tmpL = tmpL - 0x7e + 0x3fe;
  55
  56     /* set the Exponent */
  57     SHL32(Res, tmpL, 52);
  58
  59     /* set the Mantisse */
  60     tmpL = y & IEEESPMantisse_Mask;
  61     SHL32(tmpQ, tmpL, 29);
  62     OR64Q(Res, tmpQ);
  63
  64     if (y < 0)
  65     {
  66         OR64QC(Res,  IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo);
  67         SetSR( Negative_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  68     }
  69
  70     return Res;
  71
  72     AROS_LIBFUNC_EXIT
  73 }