workbench/libs/mathieeedoubbas/ieeedpcmp.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         Compares two IEEE double precision numbers
  11
  12     RESULT
  13        <code>
  14        +1 : y > z
  15         0 : y = z
  16        -1 : y < z
  17
  18         Flags:
  19           zero     : y = z
  20           negative : y < z
  21           overflow : 0
  22        </code>
  23
  24     NOTES
  25
  26     EXAMPLE
  27
  28     BUGS
  29
  30     SEE ALSO
  31
  32     INTERNALS
  33 */
  34
  35 AROS_LHQUAD2(LONG, IEEEDPCmp,
  36     AROS_LHAQUAD(double, y, D0, D1),
  37     AROS_LHAQUAD(double, z, D2, D3),
  38     struct MathIeeeDoubBasBase *, MathIeeeDoubBasBase, 7, MathIeeeDoubBas
  39 )
  40 {
  41     AROS_LIBFUNC_INIT
  42
  43     QUAD * Qy = (QUAD *)&y;
  44     QUAD * Qz = (QUAD *)&z;
  45
  46     if (is_eq(*Qy,*Qz))
  47     {
  48         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  49         return 0;
  50     }
  51
  52     if (is_lessSC(*Qy,0,0) /* y < 0 */ && is_lessSC(z,0,0) /* z < 0 */)
  53     {
  54         NEG64(*Qy);
  55         NEG64(*Qz);
  56         if (is_greater(*Qy,*Qz) /* -y > -z */ )
  57         {
  58             SetSR(0,  Zero_Bit | Negative_Bit | Overflow_Bit);
  59             return 1;
  60         }
  61         else
  62         {
  63             SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  64             return -1;
  65         }
  66     }
  67
  68     if ( is_less(*Qy,*Qz)  /* (QUAD)y < (QUAD)z */ )
  69     {
  70         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  71         return -1;
  72     }
  73     else
  74     {
  75         SetSR(0,  Zero_Bit | Negative_Bit | Overflow_Bit);
  76         return 1;
  77     }
  78
  79     AROS_LIBFUNC_EXIT
  80 }