workbench/libs/mathtrans/spsinh.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include "mathtrans_intern.h"
   7
   8 /*
   9     FUNCTION
  10       Calculate the hyperbolic sine of the ffp number
  11
  12     RESULT
  13       Motorola fast floating point number
  14
  15       flags:
  16         zero     : result is zero
  17         negative : result is negative
  18         overflow : result is too big for ffp format
  19
  20     NOTES
  21
  22     EXAMPLE
  23
  24     BUGS
  25
  26     SEE ALSO
  27
  28     INTERNALS
  29       sinh(x) = (1/2)*( e^x- e^(-x) )
  30
  31       sinh( |x| >= 44 ) = infinity;
  32       sinh( |x| >=  9 ) = (1/2) * (e^x);
  33
  34     HISTORY
  35 */
  36
  37 AROS_LH1(float, SPSinh,
  38     AROS_LHA(float, fnum1, D0),
  39     struct Library *, MathTransBase, 10, MathTrans
  40 )
  41 {
  42     AROS_LIBFUNC_INIT
  43
  44     ULONG Res;
  45     LONG tmp;
  46
  47     /* sinh(-x) = -sinh(x) */
  48     Res = SPExp(fnum1 & (FFPMantisse_Mask + FFPExponent_Mask) );
  49
  50     if ( FFP_Pinfty == Res )
  51     {
  52         SetSR(Overflow_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  53         return Res;
  54     }
  55
  56     tmp = (fnum1 & FFPExponent_Mask) - 0x41;
  57
  58     if ( tmp <= 2  || (tmp == 3 && (fnum1 & FFPMantisse_Mask) < 0x90000000) )
  59     {
  60         Res = SPAdd(Res, ((ULONG)SPDiv(Res, one) | FFPSign_Mask ));
  61     }
  62
  63     /* Res = Res / 2 */
  64
  65     /* should be (char(Res))-- , but gcc on Linux screws up the result! */
  66
  67     tmp = Res & 0xFFFFFF00;
  68     Res -= sizeof(char);
  69     Res = Res | tmp;
  70
  71     if ( 0 == Res || (char)Res < 0 )
  72     {
  73         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  74         return 0;
  75     }
  76
  77     /* if the argument was negative, the result is also negative */
  78     if ((char)fnum1 < 0 )
  79     {
  80         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  81         return (Res | FFPSign_Mask);
  82     }
  83
  84     return Res;
  85
  86     AROS_LIBFUNC_EXIT
  87 }