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
  10     NAME */
  11
  12         AROS_LHQUAD1(LONG, IEEEDPTst,
  13
  14 /*  SYNOPSIS */
  15         AROS_LHAQUAD(double, y, D0, D1),
  16
  17 /*  LOCATION */
  18         struct MathIeeeDoubBasBase *, MathIeeeDoubBasBase, 8, MathIeeeDoubBas)
  19
  20 /*  FUNCTION
  21         Compare a IEEE double precision floting point number against zero.
  22
  23     INPUTS
  24
  25     RESULT
  26         +1 : y > 0.0
  27          0 : y = 0.0
  28         -1 : y < 0.0
  29
  30         Flags:
  31           zero     : result is zero
  32           negative : result is negative
  33           overflow : 0
  34
  35     BUGS
  36
  37     INTERNALS
  38         ALGORITHM:
  39         Sign is negative: return -1
  40         y == 0          : return 0
  41         Otherwise       : return 1
  42
  43 *****************************************************************************/
  44 {
  45     AROS_LIBFUNC_INIT
  46
  47     QUAD * Qy = (QUAD *)&y;
  48
  49     /* y is negative */
  50     if (is_lessSC(*Qy, 0x0, 0x0) /* y < 0 */)
  51     {
  52         SetSR(Negative_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  53         return -1;
  54     }
  55
  56     /* fnum1 is zero */
  57     if (is_eqC(*Qy, 0x0, 0x0) /* y == 0 */)
  58     {
  59         SetSR(Zero_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  60         return 0;
  61     }
  62
  63     /* fnum1 is positive */
  64     SetSR(0, Zero_Bit | Overflow_Bit | Negative_Bit );
  65
  66     return 1;
  67
  68     AROS_LIBFUNC_EXIT
  69 }