I am trying to write an HDL code for converting floating point numbers in IEEE-754 format to integers and vice-versa. For eg.

    for floatToInt operation:
    input = 8.9 (in IEEE-754 format)
    output = 9  (an integer number)

    for intToFloat operation:
    input = 10 (an integer number)
    output = 10.00 (in IEEE-754 format)

In my code, I also need to take care of all the exceptions that might be generated while doing this. Please explain or point me to a good article which exhaustively explains the general procedure/algorithm to do so. I would be very obliged. Thanks in advance.

  • 1
    \$\begingroup\$ Google a paper called "What every computer scientist should know about floating point arithmetic". This should give you enough background to answer your own question. \$\endgroup\$
    – The Photon
    Sep 21, 2015 at 8:07
  • \$\begingroup\$ Use the VHDL-2008 fixed and floating point libraries, which are designed to be synthesisable. There are versions for earlier VHDL dialects, see vhdl.org/fphdl \$\endgroup\$
    – user16324
    Sep 21, 2015 at 10:14

1 Answer 1


How about just casting them:

entity x is
end entity x;
architecture STR of x is
    signal i: integer;
    signal r: real;
    i <= integer(r);
    r <= real(i);
end architecture STR;
  • \$\begingroup\$ I am designing a Floating Point Unit and hence must write the codes explicitly \$\endgroup\$
    – titan
    Sep 21, 2015 at 8:59

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