jojo26
Newbie level 5
hey i'm a newbie ,i want to have a simple substraction between two std logic vectors so i converted them into signed,but when i tested this code it didn't work correctly for example 8 +(-5) gave me (-1021) istead of 3 !!!
the compilation is working.
thanks a lot
regards
jojo26
PHP:
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity sub is
port (
clk : in std_logic;
rst : in std_logic;
a,b : in std_logic_vector (10 downto 0);
c : out std_logic_vector (11 downto 0)
);
end sub;
architecture beh of sub is
signal p1,p2,p3 :signed (11 downto 0);
begin
p1 <= signed ('0'& a) ;
p2 <= signed ('0'& b) ;
process (clk, rst)
begin
if (rst = '1') then
p3 <= "000000000000";
elsif (clk'event and clk='1') then
p3 <= p1 + p2;
end if;
end process;
c<= std_logic_vector(p3);
end beh;the compilation is working.
thanks a lot
regards
jojo26