workbench/libs/mathieeedoubbas/ieeedpcmp.c

   1 /*
   2     Copyright © 1995-2017, 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         y - IEEE double precision floating point number.
  26         z - IEEE double precision floating point number.
  27
  28     RESULT
  29         c -
  30             +1: y > z
  31              0: y = z
  32             -1: y < z
  33
  34         Flags:
  35           zero     : y = z
  36           negative : y < z
  37           overflow : 0
  38
  39     NOTES
  40
  41     EXAMPLE
  42
  43     BUGS
  44
  45     SEE ALSO
  46         IEEEDPTst()
  47
  48     INTERNALS
  49
  50 *****************************************************************************/
  51 {
  52     AROS_LIBFUNC_INIT
  53
  54     QUAD * Qy = (QUAD *)&y;
  55     QUAD * Qz = (QUAD *)&z;
  56
  57     if (is_eq(*Qy,*Qz))
  58     {
  59         SetSR(Zero_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  60         return 0;
  61     }
  62
  63     if (is_lessSC(*Qy,0,0) /* y < 0 */ && is_lessSC(z,0,0) /* z < 0 */)
  64     {
  65         NEG64(*Qy);
  66         NEG64(*Qz);
  67         if (is_greater(*Qy,*Qz) /* -y > -z */ )
  68         {
  69             SetSR(0,  Zero_Bit | Negative_Bit | Overflow_Bit);
  70             return 1;
  71         }
  72         else
  73         {
  74             SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  75             return -1;
  76         }
  77     }
  78
  79     if ( is_less(*Qy,*Qz)  /* (QUAD)y < (QUAD)z */ )
  80     {
  81         SetSR(Negative_Bit, Zero_Bit | Negative_Bit | Overflow_Bit);
  82         return -1;
  83     }
  84     else
  85     {
  86         SetSR(0,  Zero_Bit | Negative_Bit | Overflow_Bit);
  87         return 1;
  88     }
  89
  90     AROS_LIBFUNC_EXIT
  91 }