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
  10     NAME */
  11
  12         AROS_LHQUAD1(LONG, IEEEDPFix,
  13
  14 /*  SYNOPSIS */
  15         AROS_LHAQUAD(double, y, D0, D1),
  16
  17 /*  LOCATION */
  18         struct MathIeeeDoubBasBase *, MathIeeeDoubBasBase, 5, MathIeeeDoubBas)
  19
  20 /*  FUNCTION
  21         Convert IEEE double precision floating point number to integer
  22
  23     INPUTS
  24
  25     RESULT
  26         absolute value of y
  27
  28         Flags:
  29           zero     : result is zero
  30           negative : result is negative
  31           overflow : ieeedp out of integer-range
  32
  33     BUGS
  34
  35     INTERNALS
  36
  37 *****************************************************************************/
  38 {
  39     AROS_LIBFUNC_INIT
  40
  41     LONG Res, Shift, tmp;
  42     QUAD y2;
  43     QUAD * Qy = (QUAD *)&y;
  44
  45     tmp = Get_High32of64(*Qy) & IEEEDPExponent_Mask_Hi;
  46
  47     if ( tmp > 0x41d00000 )
  48     {
  49     if( is_lessSC(*Qy, 0x0, 0x0))
  50     {
  51     SetSR(Overflow_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  52     return 0x80000000;
  53     }
  54     else
  55     {
  56     SetSR(Overflow_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  57     return 0x7fffffff;
  58     }
  59     }
  60
  61
  62     if(
  63            is_eqC(*Qy, 0x0, 0x0)
  64         || is_eqC(*Qy,IEEEDPSign_Mask_Hi, IEEEDPSign_Mask_Lo)
  65     ) /* y=+-0; */
  66     {
  67         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  68         return 0;
  69     }
  70
  71     Shift = (Get_High32of64(*Qy) & IEEEDPExponent_Mask_Hi) >> 20;
  72     Shift = 0x433 - Shift;
  73     tmp = Get_High32of64(*Qy);
  74     AND64QC(*Qy, IEEEDPMantisse_Mask_Hi, IEEEDPMantisse_Mask_Lo);
  75     OR64QC(*Qy, 0x00100000, 0x00000000);
  76     SHRU64(y2, *Qy , Shift);
  77     Res = Get_Low32of64(y2);
  78
  79     /* Test for a negative sign  */
  80     if (tmp < 0) /* y < 0 */
  81     {
  82         Res = -Res;
  83         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  84     }
  85
  86     return Res;
  87
  88     AROS_LIBFUNC_EXIT
  89 }