workbench/libs/mathieeedoubtrans/ieeedpcos.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include "mathieeedoubtrans_intern.h"
   7
   8 /*
   9     FUNCTION
  10       Calculate the cosine of a given IEEE double precision number in radians
  11
  12     RESULT
  13       IEEE double precision floating point number
  14
  15       flags:
  16         zero     : result is zero
  17         negative : result is negative
  18         overflow : 0
  19
  20     NOTES
  21
  22     EXAMPLE
  23
  24     BUGS
  25
  26     SEE ALSO
  27
  28     INTERNALS
  29       cos (x) = sin (x+ pi/2);
  30
  31     HISTORY
  32 */
  33
  34 AROS_LHQUAD1(double, IEEEDPCos,
  35     AROS_LHAQUAD(double, y, D0, D1),
  36     struct MathIeeeDoubTransBase *, MathIeeeDoubTransBase, 7, MathIeeeDoubTrans
  37 )
  38 {
  39     AROS_LIBFUNC_INIT
  40
  41     LONG tmp;
  42     QUAD z,Res, ysquared, yabs, Qtmp;
  43     AND64C
  44     (
  45         yabs, y,
  46         (IEEEDPMantisse_Mask_Hi | IEEEDPExponent_Mask_Hi),
  47         (IEEEDPMantisse_Mask_Lo | IEEEDPExponent_Mask_Lo)
  48     );
  49
  50     if (is_eqC(yabs, IEEEDPPInfty_Hi, IEEEDPPInfty_Lo))
  51     {
  52         SetSR(Overflow_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  53         Set_Value64C(Res, IEEEDPNAN_Hi, IEEEDPNAN_Lo);
  54         return Res;
  55     }
  56
  57     z = IEEEDPFloor(IEEEDPDiv(yabs, pi));
  58     Qtmp  = IEEEDPMul(z,pi);
  59     OR64QC(tmp, IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo) /* Qtmp=-Qtmp */
  60     yabs = IEEEDPAdd(yabs, Qtmp);
  61     if (is_greaterC(yabs, pio2_Hi, pio2_Lo))
  62     {
  63         OR64QC(Qtmp, IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo) /* Qtmp=-Qtmp */
  64         yabs  =IEEEDPAdd(pi, yabs);
  65         tmp = TRUE;
  66     }
  67     else
  68     {
  69         tmp = FALSE;
  70     }
  71
  72     ysquared = IEEEDPMul(yabs,yabs);
  73     Res = IEEEDPAdd(cosf1,
  74           IEEEDPMul(ysquared,
  75           IEEEDPAdd(cosf2,
  76           IEEEDPMul(ysquared,
  77           IEEEDPAdd(cosf3,
  78           IEEEDPMul(ysquared,
  79           IEEEDPAdd(cosf4,
  80           IEEEDPMul(ysquared,
  81           IEEEDPAdd(cosf5,
  82           IEEEDPMul(ysquared,
  83           IEEEDPAdd(cosf6,
  84           IEEEDPMul(ysquared,
  85           IEEEDPAdd(cosf7,
  86           IEEEDPMul(ysquared, cosf8))))))))))))));
  87
  88     if (is_eqC(Res, 0x0, 0x0))
  89     {
  90         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  91         Set_Value64C(Res, 0x0, 0x0);
  92         return Res;
  93     }
  94
  95     if (TRUE == intern_IEEEDPisodd(z))
  96     {
  97         XOR64QC(Res, IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo);
  98     }
  99
 100     if (TRUE == tmp)
 101     {
 102         XOR64QC(Res, IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo);
 103     }
 104
 105     if (is_lessSC(Res, 0x0, 0x0))
 106     {
 107         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
 108     }
 109
 110     return Res;
 111
 112     AROS_LIBFUNC_EXIT
 113 }