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