workbench/libs/mathieeedoubbas/ieeedptst.c

   1 /*
   2     Copyright © 1995-2017, 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         Compares an IEEE double precision floting point number against zero.
  22
  23     INPUTS
  24         y - IEEE double precision floating point number.
  25
  26     RESULT
  27         c -
  28             +1: y > 0.0
  29              0: y = 0.0
  30             -1: y < 0.0
  31
  32         Flags:
  33           zero     : result is zero
  34           negative : result is negative
  35           overflow : 0
  36
  37     NOTES
  38
  39     EXAMPLE
  40
  41     BUGS
  42
  43     SEE ALSO
  44         IEEEDPCmp()
  45
  46     INTERNALS
  47         Algorithm:
  48         Sign is negative: return -1
  49         y == 0          : return 0
  50         Otherwise       : return 1
  51
  52 *****************************************************************************/
  53 {
  54     AROS_LIBFUNC_INIT
  55
  56     QUAD * Qy = (QUAD *)&y;
  57
  58     /* y is negative */
  59     if (is_lessSC(*Qy, 0x0, 0x0) /* y < 0 */)
  60     {
  61         SetSR(Negative_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  62         return -1;
  63     }
  64
  65     /* fnum1 is zero */
  66     if (is_eqC(*Qy, 0x0, 0x0) /* y == 0 */)
  67     {
  68         SetSR(Zero_Bit, Zero_Bit | Overflow_Bit | Negative_Bit);
  69         return 0;
  70     }
  71
  72     /* fnum1 is positive */
  73     SetSR(0, Zero_Bit | Overflow_Bit | Negative_Bit );
  74
  75     return 1;
  76
  77     AROS_LIBFUNC_EXIT
  78 }