An Introduction to VHDL [PDF]

UNIT – V PRINCIPLES OF HDL

CONTENTS 1.

Introduction to VHDL 1.1

2.

VHDL Program Structure 2.1 2.2

3. 4.

Package Declaration Package Body Important Packages

. -- Logical shift fills with T'LEFT. bv4 := "1001" sra 2; -- Shift right arithmetic, now bv4="0111". -- Arithmetic shift fills with element at end being vacated. bv4 := "1001" ror 2; -- Rotate right, now bv4="0110". -- Rotate wraps around. -- Integer argument to any shift operator may be negative or zero. if (pi*2.718)/2.718 = 3.14 then wait; end if; -- This is unreliable. if (abs(((pi*2.718)/2.718)-3.14)