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numeric_std is a library package defined for VHDL This package provides arithmetic functions for vectors. Overrides of std_logic_vector are defined for signed and unsigned arithmetic. This package 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; 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Numeric std」の詳細全文を読む スポンサード リンク
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