workbench/libs/mathieeedoubbas/ieeedpfix.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include "mathieeedoubbas_intern.h"
   7
   8 /*
   9     FUNCTION
  10         Convert IEEE double precision floating point number to integer
  11
  12     RESULT
  13         absolute value of y
  14
  15         Flags:
  16           zero     : result is zero
  17           negative : result is negative
  18           overflow : ieeedp out of integer-range
  19
  20     NOTES
  21
  22     EXAMPLE
  23
  24     BUGS
  25
  26     SEE ALSO
  27
  28     INTERNALS
  29
  30     HISTORY
  31 */
  32
  33 AROS_LHQUAD1(LONG, IEEEDPFix,
  34     AROS_LHAQUAD(double, y, D0, D1),
  35     struct MathIeeeDoubBasBase *, MathIeeeDoubBasBase, 5, MathIeeeDoubBas
  36 )
  37 {
  38     AROS_LIBFUNC_INIT
  39
  40     LONG Res, Shift, tmp;
  41     QUAD y2;
  42     QUAD * Qy = (QUAD *)&y;
  43
  44     tmp = Get_High32of64(*Qy) & IEEEDPExponent_Mask_Hi;
  45
  46     if ( tmp > 0x41d00000 )
  47     {
  48     if( is_lessSC(*Qy, 0x0, 0x0))
  49     {
  50     SetSR(Overflow_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  51     return 0x80000000;
  52     }
  53     else
  54     {
  55     SetSR(Overflow_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  56     return 0x7fffffff;
  57     }
  58     }
  59
  60
  61     if(
  62            is_eqC(*Qy, 0x0, 0x0)
  63         || is_eqC(*Qy,IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo)
  64     ) /* y=+-0; */
  65     {
  66         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  67         return 0;
  68     }
  69
  70     Shift = (Get_High32of64(*Qy) & IEEEDPExponent_Mask_Hi) >> 20;
  71     Shift = 0x433 - Shift;
  72     tmp = Get_High32of64(*Qy);
  73     AND64QC(*Qy, IEEEDPMantisse_Mask_Hi, IEEEDPMantisse_Mask_Lo);
  74     OR64QC(*Qy, 0x00100000, 0x00000000);
  75     SHRU64(y2, *Qy , Shift);
  76     Res = Get_Low32of64(y2);
  77
  78     /* Test for a negative sign  */
  79     if (tmp < 0) /* y < 0 */
  80     {
  81         Res = -Res;
  82         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  83     }
  84
  85     return Res;
  86
  87     AROS_LIBFUNC_EXIT
  88 }