workbench/libs/mathieeedoubbas/ieeedpceil.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(double, IEEEDPCeil,
  13
  14 /*  SYNOPSIS */
  15         AROS_LHAQUAD(double, y, D0, D1),
  16
  17 /*  LOCATION */
  18         struct MathIeeeDoubBasBase *, MathIeeeDoubBasBase, 16, MathIeeeDoubBas)
  19
  20 /*  FUNCTION
  21         Calculates the ceiling value of an IEEE double precision number.
  22
  23     INPUTS
  24         y - IEEE double precision floating point number.
  25
  26     RESULT
  27         x - ceiling of y.
  28
  29         Flags:
  30           zero     : result is zero
  31           negative : result is negative
  32           overflow : 0
  33
  34     NOTES
  35
  36     EXAMPLE
  37
  38     BUGS
  39
  40     SEE ALSO
  41         IEEEDPFloor(), IEEEDPFix()
  42
  43     INTERNALS
  44         Algorithm:
  45         Ceil(y) = - Floor(-y)
  46
  47 *****************************************************************************/
  48 {
  49     AROS_LIBFUNC_INIT
  50
  51     QUAD * Qy = (QUAD *)&y;
  52
  53     if (is_eqC((*Qy),0,0))
  54     {
  55         SetSR(Zero_Bit, Negative_Bit|Overflow_Bit|Zero_Bit);
  56         return y;
  57     }
  58
  59     XOR64QC((*Qy), IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo);
  60     /* Ceil(y) = -Floor(-y); */
  61     y = IEEEDPFloor(y);
  62     if (is_eqC((*Qy), 0x0, 0x0))
  63     {
  64         Set_Value64C((*Qy), 0, 0);
  65         return y;
  66     }
  67     else
  68     {
  69         XOR64QC((*Qy), IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo );
  70         return y;
  71     }
  72
  73     AROS_LIBFUNC_EXIT
  74 }