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
  10     NAME */
  11
  12         AROS_LHQUAD2(LONG, IEEEDPCmp,
  13
  14 /*  SYNOPSIS */
  15         AROS_LHAQUAD(double, y, D0, D1),
  16         AROS_LHAQUAD(double, z, D2, D3),
  17
  18 /*  LOCATION */
  19         struct MathIeeeDoubBasBase *, MathIeeeDoubBasBase, 7, MathIeeeDoubBas)
  20
  21 /*  FUNCTION
  22         Compares two IEEE double precision numbers
  23
  24     INPUTS
  25
  26     RESULT
  27        +1 : y > z
  28         0 : y = z
  29        -1 : y < z
  30
  31         Flags:
  32           zero     : y = z
  33           negative : y < z
  34           overflow : 0
  35
  36     BUGS
  37
  38     INTERNALS
  39
  40 *****************************************************************************/
  41 {
  42     AROS_LIBFUNC_INIT
  43
  44     QUAD * Qy = (QUAD *)&y;
  45     QUAD * Qz = (QUAD *)&z;
  46
  47     if (is_eq(*Qy,*Qz))
  48     {
  49         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  50         return 0;
  51     }
  52
  53     if (is_lessSC(*Qy,0,0) /* y < 0 */ && is_lessSC(z,0,0) /* z < 0 */)
  54     {
  55         NEG64(*Qy);
  56         NEG64(*Qz);
  57         if (is_greater(*Qy,*Qz) /* -y > -z */ )
  58         {
  59             SetSR(0,  Zero_Bit | Negative_Bit | Overflow_Bit);
  60             return 1;
  61         }
  62         else
  63         {
  64             SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  65             return -1;
  66         }
  67     }
  68
  69     if ( is_less(*Qy,*Qz)  /* (QUAD)y < (QUAD)z */ )
  70     {
  71         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  72         return -1;
  73     }
  74     else
  75     {
  76         SetSR(0,  Zero_Bit | Negative_Bit | Overflow_Bit);
  77         return 1;
  78     }
  79
  80     AROS_LIBFUNC_EXIT
  81 }