numeric_std

numeric_std is a library package defined for <a href="/facts/VHDL/H6Exdjfs">VHDL</a>. It provides <a href="/facts/Arithmetic_functions/hULxwsgm">arithmetic functions</a> for vectors. Overrides of std_logic_vector are defined for <a href="/facts/Signedness/6vTRuxPk">signed and unsigned</a> arithmetic. It defines numeric types and arithmetic functions for use with synthesis tools. Two numeric types are defined: UNSIGNED (represents UNSIGNED number in vector form) and SIGNED (represents a SIGNED number in vector form). The base element type is type STD_LOGIC. The leftmost bit is treated as the most significant bit. Signed vectors are represented in two's complement form. This package contains overloaded arithmetic operators on the SIGNED and UNSIGNED types. The package also contains useful type conversions functions.
It is typically included at the top of a design unit:

 library ieee;
 use ieee.std_logic_1164.all;	-- standard unresolved logic UX01ZWLH-
 use ieee.numeric_std.all; -- for the signed, unsigned types and arithmetic ops

The alternative numeric package ieee.std_logic_arith should not be used for new designs. This package does not provide overrides for mixing signed and unsigned functions. This package includes definitions for the following (not all of which are synthesizable):

numeric_std open-in-new

numeric_std