workbench/libs/mathieeedoubbas/ieeedptst.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include "mathieeedoubbas_intern.h"
   7
   8 /*
   9     FUNCTION
  10         Compare a IEEE double precision floting point number against zero.
  11
  12     RESULT
  13        <code>
  14         +1 : y > 0.0
  15          0 : y = 0.0
  16         -1 : y < 0.0
  17
  18         Flags:
  19           zero     : result is zero
  20           negative : result is negative
  21           overflow : 0
  22        </code>
  23
  24     NOTES
  25
  26     EXAMPLE
  27
  28     BUGS
  29
  30     SEE ALSO
  31
  32     INTERNALS
  33       ALGORITHM:
  34         Sign is negative: return -1
  35         y == 0          : return 0
  36         Otherwise       : return 1
  37 */
  38
  39 AROS_LHQUAD1(LONG, IEEEDPTst,
  40     AROS_LHAQUAD(double, y, D0, D1),
  41     struct MathIeeeDoubBasBase *, MathIeeeDoubBasBase, 8, MathIeeeDoubBas
  42 )
  43 {
  44     AROS_LIBFUNC_INIT
  45
  46     QUAD * Qy = (QUAD *)&y;
  47
  48     /* y is negative */
  49     if (is_lessSC(*Qy, 0x0, 0x0) /* y < 0 */)
  50     {
  51         SetSR(Negative_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  52         return -1;
  53     }
  54
  55     /* fnum1 is zero */
  56     if (is_eqC(*Qy, 0x0, 0x0) /* y == 0 */)
  57     {
  58         SetSR(Zero_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  59         return 0;
  60     }
  61
  62     /* fnum1 is positive */
  63     SetSR(0, Zero_Bit | Overflow_Bit | Negative_Bit );
  64
  65     return 1;
  66
  67     AROS_LIBFUNC_EXIT
  68 }