Concatenation
Formal Definition
Predefined adding operator for any
onedimensional array type.
Description
The concatenation operator (denoted as &)
composes two onedimensional arrays into a larger one of the same
type. A single element can be used as any of the two operands of
concatenation. If two single elements are concatenated, then the
result can be of any array type (as long as it is compatible with the
type of the operands).
The resulting array is composed of the elements of the left operand
(in lefttoright order) followed by the elements of the right
operand (in the same order). The direction of the resulting array is
the same as of the left operand, unless the left operand is a null
array, in which case the direction of the result is that of the right operand.
Examples
variable ByteDat :
Bit_Vector(7 downto 0);
alias Sign : Bit is ByteDat(7);
alias Modulus : Bit_Vector(6 downto
0) is ByteDat(6 downto 0);
constant FourZeros :
Bit_Vector(3 downto 0) := "0000";
constant ResetHigh :
Bit_Vector(7 downto 0) :=
FourZeros & "1111";
constant ResetAll :
Bit_Vector(7 downto 0) :=
FourZeros & FourZeros;
ByteDat := '1' & Modulus;
Important Notes
