VHDL Kompakt - CES

2.4 Attribute
Beispiel
Bereichsgrenzen
type T_RAM_DAT is array (0 to 511) of integer;
variable RAM_DAT : T_RAM_DAT;
...
for I in RAM_DAT’low to RAM_DAT’high loop
... s.u. Bereiche
Bereichsgrenzen mehrdimensional
variable MEM (0 to 15, 7 downto 0) of MEM_DAT;
...
MEM’left(1) = 0
MEM’right(1) = 15
MEM’left(2) = 7
MEM’right(2) = 0
MEM’low(2) = 0
MEM’high(2) = 7
Arraylängen
type BIT4 is array (3 downto 0) of bit;
type BITX is array (10 to 30) of bit;
...
BIT4’length = 4
BITX’length = 21
Bereiche
function BV_TO_INT (VEC: bit_vector) return integer is
...
begin
for I in VEC’range loop
...
21