Package: ghdl
Version: 0.29+gcc4.3.4+dfsg-1
Severity: normal
--- Please enter the report below this line. ---
I have the following vhdl code :
--------------------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity tb_test is end;
architecture arch_tb of tb_test is
signal reset_s, clk_s : std_logic;
signal i_s : integer;
signal u_s : unsigned(7 downto 0);
begin
reset : reset_s <= '0',
'1' after 20 ns,
'0' after 400 ns;
clock : process begin
clk_s <= '0';
wait for 100 ns;
clk_s <= '1';
wait for 100 ns;
end process clock;
process (reset_s, clk_s) begin
if reset_s = '1' then
report integer'image(i_s); -- Will report -2147483648
i_s <= 0;
elsif rising_edge(clk_s) then
i_s <= 3;
end if;
end process;
u_s <= to_unsigned(i_s, 8); -- Will give a bound check failure
end architecture arch_tb;
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When simulating this code, the signal i_s is at first uninitialized and
has the value -2147483648.
Then, as shown below, a bound check failure is raised because it is
trying to convert a negativ value to an unsigned at the line "u_s <=
to_unsigned(i_s, 8)".
./tb_test:error: bound check failed (#11)
./tb_test:error: simulation failed
ghdl: compilation error
It is possible to avoid that by initialising i_s when it is declared,
but signals are usually initialised during a reset and that's what is
trying to make this code but it doesn't have time to do it before the
failure.
I think the best would be to put a warning instead an error and leave
the signal u_s to its uninitialised value ("UUUUUUUU").
Bye
Jonas
--- System information. ---
Architecture: i386
Kernel: Linux 2.6.32-5-686
Debian Release: squeeze/sid
700 testing ftp.ch.debian.org
600 unstable ftp.ch.debian.org
1 experimental ftp.ch.debian.org
--- Package information. ---
Depends (Version) | Installed
=============================-+-=============
libc6 (>= 2.7) | 2.11.1-3
libgcc1 (>= 1:4.1.1) | 1:4.4.4-4
libgmp3c2 | 2:4.3.2+dfsg-1
libgnat-4.4 (>= 4.4.3-1) | 4.4.4-4
libmpfr1ldbl | 2.4.2-3
gnat-4.4 | 4.4.4-4
zlib1g-dev | 1:1.2.3.4.dfsg-3
Recommends (Version) | Installed
=========================-+-===========
gtkwave | 3.3.6-1
Package's Suggests field is empty.
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