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
  10     NAME */
  11
  12         AROS_LH1(float, SPSinh,
  13
  14 /*  SYNOPSIS */
  15         AROS_LHA(float, fnum1, D0),
  16
  17 /*  LOCATION */
  18         struct Library *, MathTransBase, 10, MathTrans)
  19
  20 /*  FUNCTION
  21         Calculate the hyperbolic sine of the ffp number
  22
  23     INPUTS
  24
  25     RESULT
  26         Motorola fast floating point number
  27
  28         flags:
  29         zero     : result is zero
  30         negative : result is negative
  31         overflow : result is too big for ffp format
  32
  33     BUGS
  34
  35     INTERNALS
  36         sinh(x) = (1/2)*( e^x- e^(-x) )
  37
  38         sinh( |x| >= 44 ) = infinity;
  39         sinh( |x| >=  9 ) = (1/2) * (e^x);
  40
  41 *****************************************************************************/
  42 {
  43     AROS_LIBFUNC_INIT
  44
  45     ULONG Res;
  46     LONG tmp;
  47
  48     /* sinh(-x) = -sinh(x) */
  49     Res = SPExp(fnum1 & (FFPMantisse_Mask + FFPExponent_Mask) );
  50
  51     if ( FFP_Pinfty == Res )
  52     {
  53         SetSR(Overflow_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  54         return Res;
  55     }
  56
  57     tmp = (fnum1 & FFPExponent_Mask) - 0x41;
  58
  59     if ( tmp <= 2  || (tmp == 3 && (fnum1 & FFPMantisse_Mask) < 0x90000000) )
  60     {
  61         Res = SPAdd(Res, ((ULONG)SPDiv(Res, one) | FFPSign_Mask ));
  62     }
  63
  64     /* Res = Res / 2 */
  65
  66     /* should be (char(Res))-- , but gcc on Linux screws up the result! */
  67
  68     tmp = Res & 0xFFFFFF00;
  69     Res -= sizeof(char);
  70     Res = Res | tmp;
  71
  72     if ( 0 == Res || (char)Res < 0 )
  73     {
  74         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  75         return 0;
  76     }
  77
  78     /* if the argument was negative, the result is also negative */
  79     if ((char)fnum1 < 0 )
  80     {
  81         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  82         return (Res | FFPSign_Mask);
  83     }
  84
  85     return Res;
  86
  87     AROS_LIBFUNC_EXIT
  88 }