AR# 8369: 3.1i XST - What types of Generate Blocks are supported in VHDL?
AR# 8369
3.1i XST - What types of Generate Blocks are supported in VHDL?
Description
General Description:
What types of Generate Blocks are supported in VHDL?
(NOTE: The constructs reported below are supported in the 4.1i software release.)
Solution
Structural Generate:
This is supported by XST.
This is a concurrent statement that is replicated to produce multiple concurrent statements.
architecture block of register is
-- signal and component declarations
begin
cell_array : for bit_index in 0 to 10 generate
signal data : std_logic;
cell_storage : D_flipflop
port map (clk=>clock, d=>data_in(bit_index),
q=>data_unbuffered);
cell_buffer : tristate_buffer
port map (a=>data_unbuffered, en=>out_enable,
y=>data_out(bit_index);
end generate cell_array;
end architecture block;
VHDL supports two types of Generate Blocks, Structural and Process.
Process used in Generate:
This is not supported by XST.
The signals "ifetch_freq", "write_freq", and "read_freq", and the process "access_monitor" are only included in the design if the generic constant instrumented is true.
entity computer is
generic (instrumented : boolean :=false);
port (....);
end entity computer;
architecture block of computer is
-- signal and component declarations
begin
instrumentation : if instrumented generate
signal ifetch_freq, write_freq, read_freq : real := 0.0;