Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Cyclone II Output Number Format?

Does anyone know the number format used by the Cyclone II, signed arithmetic, 2's complement etc.? Many thanks

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Thanks amilcar. Does it verify this somewhere in the documentation?

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    The question doesn't make sense for types that are defined in standard libraries, because Altera can't use a format at will. IEEE VHDL libraries specify explicitely two's complement for SIGNED type. In case of doubt, you can refer to the VHDL standard and the library code.

    Consequently, Altera is using the same numeric representation for SIGNED numbers, that are interfaced by an untypified bit vector, as in numeric MegaFunctions:

    --- Quote Start ---

    The signed representation for all library of parameterized modules (LPM) megafunctions is two's complement.

    --- Quote End ---

    Most users think it's obvious and don't ask about.