Re: IEEE float I/O in DEC Ada

[Gautier <Gautier.deMontmollin@Maths.UniNe.CH>]

Thank you all for your help!

The link to file ada$predefined:system_.adc
was decisive. The conversions work - I precise
that the machine is an Alphaserver 8420 under OpenVMS V6.2.

Testing works - apart a carriage return that
DEC Ada adds after each binary record !

It seems even usual; dir /full outputs:
...
Record format:      Fixed length 4 byte records
Record attributes:  Carriage return carriage control

But now the situation is under control...

Thank you again!

-- 
Gautier

--------
http://members.xoom.com/gdemont/

PS: test programs.

-- Test IEEE float output on AXP with DEC Ada

with system;
with sequential_io;
with text_io;                use text_io;

procedure wr_ieee is

  subtype ieee_real is system.ieee_single_float;
  subtype real is long_float;

  package rio  is new float_io(real);      use rio;
  package irio is new float_io(ieee_real); use irio;

  package sio is new sequential_io(ieee_real); use sio;

  f: sio.file_type;

  d: constant array(1..6) of real:=
    (  1.2345678901234567890,  1.0e40,  1.0e-39,
      -1.2345678901234567890, -1.0e40, -1.0e-39 );

  function To_IEEE(r: real) return ieee_real is
    begin
      if r > real(ieee_real'last) then      -- overflow
        return ieee_real'last;
      elsif r < real(ieee_real'first) then  -- overflow
        return ieee_real'first;
--      elsif abs(r) < real(ieee_real'small) then -- underflow (seems
useless)
--        return 0.0;
      else
        return ieee_real(r);
      end if;
    end To_IEEE;

  begin
    for i in d'range loop
      Put("   real  ");    Put(d(i));
      Put("   ieee  ");    Put(to_ieee(d(i)));
      New_Line;
    end loop;
    Create(f, name=> "IEEE.DAT");
    for i in d'range loop Write(f, to_ieee(d(i)) ); end loop;
    Close(f);
  end wr_ieee;

$ ru wr_ieee
   real   1.23456789012346E+00   ieee   1.23457E+00
   real   1.00000000000000E+40   ieee   3.40282E+38
   real   1.00000000000000E-39   ieee   0.00000E+00
   real  -1.23456789012346E+00   ieee  -1.23457E+00
   real  -1.00000000000000E+40   ieee  -3.40282E+38
   real  -1.00000000000000E-39   ieee   0.00000E+00

-- Test IEEE float input on PC with GNAT

with sequential_io;
with text_io;                use text_io;

procedure rd_ieee is

  subtype ieee_real is float;
  package irio is new float_io(ieee_real); use irio;
  package sio is new sequential_io(ieee_real); use sio;

  f: sio.file_type;
  d: array(1..6) of ieee_real;

  begin
    Open(f, in_file, "IEEE.DAT");
    for i in d'range loop
      Read(f,d(i));
      Put("   ieee  ");    Put(d(i));
      New_Line;
    end loop;
    Close(f);
  end;

C:\USERS\GAUTIER\ADA\TESTS>rd_ieee.exe
   ieee   1.23457E+00
   ieee   3.40282E+38
   ieee   0.00000E+00
   ieee  -1.23457E+00
   ieee  -3.40282E+38
   ieee   0.00000E+00