workbench/libs/mathieeesingtrans/ieeespsinh.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include "mathieeesingtrans_intern.h"
   7
   8 /*****************************************************************************
   9
  10     NAME */
  11
  12         AROS_LH1(float, IEEESPSinh,
  13
  14 /*  SYNOPSIS */
  15         AROS_LHA(float, y, D0),
  16
  17 /*  LOCATION */
  18         struct Library *, MathIeeeSingTransBase, 10, MathIeeeSingTrans)
  19
  20 /*  FUNCTION
  21         Calculate the hyperbolic sine of the IEEE single precision number
  22
  23     INPUTS
  24
  25     RESULT
  26         IEEE single precision floating point number
  27
  28         flags:
  29         zero     : result is zero
  30         negative : result is negative
  31         overflow : result is too big for IEEE single precsion format
  32
  33     BUGS
  34
  35     INTERNALS
  36         sinh(x) = (1/2)*( e^x- e^(-x) )
  37
  38         sinh( |x| >=  9 ) = (1/2) * (e^x);
  39
  40 *****************************************************************************/
  41
  42 {
  43     AROS_LIBFUNC_INIT
  44
  45     LONG Res;
  46     LONG y2 = y & (IEEESPMantisse_Mask + IEEESPExponent_Mask);
  47     LONG tmp;
  48
  49     if ( IEEESP_Pinfty == y2)
  50     {
  51         SetSR(Overflow_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  52         return y;
  53     }
  54
  55     /* sinh(-x) = -sinh(x) */
  56     Res = IEEESPExp(y2);
  57
  58     if ( IEEESP_Pinfty == Res )
  59     {
  60         SetSR(Overflow_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  61         return Res;
  62     }
  63
  64     if ( y2 < 0x41100000 )
  65     {
  66         /*
  67             the following lines is neccessary or otherwise changes in
  68             the defines/mathieeesing*.h-files would have to be made!
  69         */
  70         tmp = IEEESPDiv(one, Res);
  71         Res = IEEESPAdd(Res, tmp | IEEESPSign_Mask );
  72     }
  73     /* Res = Res / 2 */
  74     Res -= 0x00800000;
  75
  76     /* at this point Res has to be positive to be valid */
  77     if ( Res <= 0)
  78     {
  79         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  80         return (y & IEEESPSign_Mask);
  81     }
  82
  83     if ( y < 0)
  84     {
  85         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  86         return (Res | IEEESPSign_Mask);
  87     }
  88
  89     return Res;
  90
  91     AROS_LIBFUNC_EXIT
  92 }