Using numeric_std and vhdl93, I cant seems to figure out how to add a std_logic signal to a std_logic_vector.
library ieee;
use ieee.numeric_std.all;
signal in_a, out1: std_logic_vector(3 downto 0);
signal s1 : std_logic;
out1 <= std_logic_vector(signed(in_a) + s1);
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity add_std_logic is
end entity;
architecture foo of add_std_logic is
signal in_a, out1: std_logic_vector(3 downto 0);
signal s1 : std_logic;
signal s1v: std_logic_vector(0 to 0);
begin
s1v <= (others => s1);
out1 <= std_logic_vector(signed(in_a) + signed(s1v));
end architecture;
architecture fum of add_std_logic is
signal in_a, out1: std_logic_vector(3 downto 0);
signal s1 : std_logic;
subtype s1v is std_logic_vector(0 to 0);
begin
out1 <= std_logic_vector(signed(in_a) + ( s1 & ""));
end architecture;
And of course you could move in_a, s1 and out1 to the port.
Related
hi i' trying to do a 4 bit ripple carry adder with VHDL. The problem is that i'm trying to do a testbench to simulate it in ModelSim, but it doesn't work. This is the code and also the code reported by ModelSim:
Full adder code:
library ieee;
use ieee.std_logic_1164.all;
entity fullAdder is
port( -- Input of the full-adder
a : in std_logic;
-- Input of the full-adder
b : in std_logic;
-- Carry input
c_i : in std_logic;
-- Output of the full-adder
o : out std_logic;
-- Carry output
c_o : out std_logic
);
end fullAdder;
architecture data_flow of fullAdder is
begin
o <= a xor b xor c_i;
c_o <= (a and b) or (b and c_i) or (c_i and a);
end data_flow;
Ripple carry adder code:
library ieee;
use ieee.std_logic_1164.all;
entity Ripple_Carry_Adder is
Port (
A: in std_logic_vector (3 downto 0);
B:in std_logic_vector (3 downto 0);
Cin:in std_logic;
S:out std_logic_vector(3 downto 0);
Cout:out std_logic
);
end Ripple_Carry_Adder;
architecture data_flow2 of Ripple_Carry_Adder is
component fullAdder
Port(
A:in std_logic;
B:in std_logic;
Cin:in std_logic;
S:out std_logic;
Cout:out std_logic
);
end component;
signal c1,c2,c3:STD_LOGIC;
begin
FA1:fullAdder port map(A(0),B(0), Cin, S(0), c1);
FA2:fullAdder port map(A(1),B(1), c1, S(1), c2);
FA3:fullAdder port map(A(2),B(2), c2, S(2), c3);
FA4:fullAdder port map(A(3),B(3), c3, S(3), Cout);
end data_flow2;
code of Ripple carry adder testbench:
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.NUMERIC_STD.ALL;
ENTITY ripple_carry_adder_tb is
end ripple_carry_adder_tb;
ARCHITECTURE behavior OF ripple_carry_adder_tb is
constant T_CLK : time := 10 ns; -- Clock period
constant T_RESET : time := 25 ns; -- Period before the reset deassertion
COMPONENT Ripple_Carry_Adder
PORT (
A:in std_logic_vector(3 downto 0);
B:in std_logic_vector(3 downto 0);
Cin:in std_logic;
S:out std_logic_vector(3 downto 0);
Cout:out std_logic
);
END COMPONENT;
signal A_tb:std_logic_vector(3 downto 0):="0000";
signal B_tb:std_logic_vector(3 downto 0):="0000";
signal Cin_tb:std_logic:='0';
signal S_tb:std_logic_vector(3 downto 0);
signal Cout_tb:std_logic;
signal clk_tb : std_logic := '0'; -- clock signal, intialized to '0'
signal rst_tb : std_logic := '0'; -- reset signal
signal end_sim : std_logic := '1';
BEGIN
clk_tb <= (not(clk_tb) and end_sim) after T_CLK / 2; -- The clock toggles after T_CLK / 2 when end_sim is high. When end_sim is forced low, the clock stops toggling and the simulation ends.
rst_tb <= '1' after T_RESET;
RP_1: Ripple_Carry_Adder PORT MAP(A=>A_tb,B=>B_tb,Cin=>Cin_tb,S=>S_tb,Cout=>Cout_tb);
d_process: process(clk_tb, rst_tb) -- process used to make the testbench signals change synchronously with the rising edge of the clock
variable t : integer := 0; -- variable used to count the clock cycle after the reset
begin
if(rst_tb = '0') then
A_tb <= "0000";
B_tb <= "0000";
Cin_tb<='0';
t := 0;
elsif(rising_edge(clk_tb)) then
A_tb<=A_tb+1;
B_tb<=B_tb+1;
t := t + 1;
if (t>32) then
end_sim <= '0';
end if;
end if;
end process;
END;
and this is errors reported by ModelSim when i trying to start simulation:
# ** Fatal: (vsim-3817) Port "c_i" of entity "fulladder" is not in the component being instantiated.
# Time: 0 ns Iteration: 0 Instance: /ripple_carry_adder_tb/RP_1/FA1 File:
C:/Users/utente/Desktop/full_adder.vhd Line: 11
# FATAL ERROR while loading design
# Error loading design
Why doesn't work? Thanks
i have created the structural and the behavioral code for a 1-bit ALU,as well as a control circuit .The control circuit decides the operation that will be conducted between two variables : a,b .
Here is my behavioral part of the code :
library ieee;
use ieee.std_logic_1164.all;
package erotima2 is
-- AND2 declaration
component myAND2
port (outnotA,outnotB: in std_logic; outAND: out std_logic);
end component;
-- OR2 declaration
component myOR2
port (outnotA,outnotB: in std_logic; outOR: out std_logic);
end component;
-- XOR2 declaration
component myXOR2
port (outnotA,outnotB: in std_logic; outXOR: out std_logic);
end component;
--fulladder declaration
component fulladder
port(CarryIn,outnotA,outnotB: in std_logic; sum,CarryOut: out std_logic);
end component;
--Ainvert declaration
component notA
port(a: in std_logic; signala: std_logic_vector(0 downto 0); outnotA: out std_logic);
end component;
--Binvert declaration
component notB
port(b: in std_logic; signalb: std_logic_vector(0 downto 0); outnotB: out std_logic);
end component;
--ControlCircuit declaration--
component ControlCircuit
port (
opcode : in std_logic_vector (2 downto 0);
signala,signalb : out std_logic_vector(0 downto 0);
operation : out std_logic_vector (1 downto 0);
CarryIn: out std_logic);
end component;
--mux4to1 declaration
component mux4to1
port(outAND, outOR, sum, outXOR: in std_logic; operation: in std_logic_vector(1 downto 0); Result: out std_logic);
end component;
end package erotima2;
--2 input AND gate
library ieee;
use ieee.std_logic_1164.all;
entity myAND2 is
port (outnotA,outnotB: in std_logic; outAND: out std_logic);
end myAND2;
architecture model_conc of myAND2 is
begin
outAND<= outnotA and outnotB;
end model_conc;
-- 2 input OR gate
library ieee;
use ieee.std_logic_1164.all;
entity myOR2 is
port (outnotA,outnotB: in std_logic; outOR: out std_logic);
end myOR2;
architecture model_conc2 of myOR2 is
begin
outOR <= outnotA or outnotB;
end model_conc2;
--2 input XOR gate
library ieee;
use ieee.std_logic_1164.all;
entity myXOR2 is
port(outnotA,outnotB: in std_logic; outXOR: out std_logic);
end myXOR2;
architecture model_conc3 of myXOR2 is
begin
outXOR <= outnotA xor outnotB;
end model_conc3;
--3 input full adder
library ieee;
use ieee.std_logic_1164.all;
entity fulladder is
port(CarryIn,outnotA,outnotB: in std_logic; sum,CarryOut: out std_logic);
end fulladder;
architecture model_conc4 of fulladder is
begin
CarryOut <= (outnotB and CarryIn) or (outnotA and CarryIn) or (outnotA and outnotB);
sum <= (outnotA and not outnotB and not CarryIn) or (not outnotA and outnotB and not CarryIn) or (not outnotA and not outnotB and CarryIn) or (outnotA and outnotB and CarryIn);
end model_conc4;
--1 input notA
library ieee;
use ieee.std_logic_1164.all;
entity notA is
port(a: in std_logic; signala:std_logic_vector(0 downto 0); outnotA: out std_logic);
end notA;
architecture model_conc6 of notA is
begin
with signala select
outnotA <= a when "0",
not a when others;
end model_conc6;
--1 input notB
library ieee;
use ieee.std_logic_1164.all;
entity notB is
port(b: in std_logic; signalb: std_logic_vector(0 downto 0); outnotB: out std_logic);
end notB;
architecture model_conc5 of notB is
begin
with signalb select
outnotB <= b when "0",
not b when others;
end model_conc5;
--4 input MUX
library ieee;
use ieee.std_logic_1164.all;
entity mux4to1 is
port(outAND, outOR, sum, outXOR: in std_logic; operation: in std_logic_vector(1 downto 0); Result: out std_logic);
end mux4to1;
architecture model_conc7 of mux4to1 is
begin
with operation select
Result<= outAND when "00",
outOR when "01",
sum when "10",
outXOR when OTHERS;
end model_conc7 ;
The behavioral part defines the logic gates of AND,OR,XOR, a full adder for numerical addition and substraction. It also contains a 4-to-1 multiplexer that chooses (depending on the value of the "operation" variable) which operation the alu will do. Lastly there is a function that inverts the variables in order to be more efficient with our logic gate usage( using the DeMorgan theorem so we don't have to create a NOR gate). The control unit initializes the variable inputs, as well as the carryIn variable of the full adder, depending on the variable "opcode". A board with every possible combination
Next is the Control Circuit part of the code, which implements the previous board.
`
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
entity ControlCircuit is
port (
opcode :in std_logic_vector (2 downto 0);
signala, signalb : out std_logic_vector(0 downto 0);
operation : out std_logic_vector(1 downto 0);
CarryIn : out std_logic);
end ControlCircuit;
architecture model_conc9 of ControlCircuit is
--signal outAND,outOR,outXOR,sum,outnotA,outnotB : std_logic;
--signal operation : out std_logic_vector(1 downto 0);
begin
process(opcode)
begin
case opcode is
--AND--
when "000"=>
operation <= "00";
signala <= "0";
signalb <= "0";
CarryIn <= '0';
--OR--
when "001" =>
operation <= "01";
signala <= "0";
signalb <= "0";
CarryIn <= '0';
--ADD--
when "011" =>
operation <= "10";
signala <= "0";
signalb <= "0";
CarryIn <= '0';
--SUB--
when "010" =>
operation <= "10";
signala <= "0";
signalb <="1";
CarryIn <= '1';
--NOR--
when "101"=>
operation <= "00";
signala <= "1";
signalb <= "1";
CarryIn <= '0';
--xor
when "100" =>
operation <= "11";
signala <= "0";
signalb <= "0";
CarryIn <= '0';
--Adiafores times--
when others =>
operation <= "00";
signala <= "0";
signalb <= "0";
CarryIn <= '0';
end case;
end process;
end model_conc9;
`
Lastly here is the code that uses all the previous parts and and an RTL diagram that shows the code's result
library IEEE;
use ieee.std_logic_1164.all;
use work.erotima2.all;
entity structural is
port (a,b: in std_logic;
opcode : in std_logic_vector ( 2 downto 0);
Result,CarryOut : out std_logic);
end structural;
architecture alu of structural is
signal outAND,outOR,outXOR,sum,outnotA,outnotB,CarryIn : std_logic;
signal signala,signalb : std_logic_vector (0 downto 0);
signal operation : std_logic_vector (1 downto 0);
begin
u0 : myAND2 port map (outnotA,outnotB,outAND);
u1 : myOR2 port map (outnotA,outnotB,outOR);
u2 : myXOR2 port map (outnotA,outnotB,outXOR);
u3 : fulladder port map (CarryIn,outnotA,outnotB,sum,CarryOut);
u4 : notA port map (a,signala,outnotA);
u5 : notB port map (b,signalb,outnotB);
u6 : mux4to1 port map (outAND, outOR,sum, outXOR, operation, Result );
u8 : ControlCircuit port map(opcode,signala,signalb,operation,CarryIn);
end alu;
Now for the tough part, i need to use the 1-bit ALU 16 times as a component, to create a 16-bit ALU. It is important to keep the control circuit independent from the rest of the code. I have tried using an std_logic_vector ( 15 downto 0) but it did not work and i would like to use the previous code segments as a component. Can anyone give any tips or ideas that will help connect 16 1-bit ALUs to a complete 16-bit ALU? Thanks in advance for those who read this massive wall of text.
Your recent comment
Yes i understand that my code is weird but we were intsructed to invert the inputs according to this diagram . As for the duplicate post, i checked before posting and they were implemented only structurally, while in my case i need to write the behavioral part too.
Explains the issue, misspellings aside. You'll notice your architecture structural of entity structural doesn't match the signals shown on the above 1 bit alu diagram which doesn't contain an instantiated ControlCircuit.
If you were to provide a design unit that matched the above diagram you can hook up the 1 bit alu carry chain while deriving the carryin for the lsb from the control block which provides a + 1 and inversion for subtraction:
library ieee;
use ieee.std_logic_1164.all;
entity alu_16_bit is
port (
a: in std_logic_vector (15 downto 0);
b: in std_logic_vector (15 downto 0);
opcode: in std_logic_vector (2 downto 0);
result: out std_logic_vector (15 downto 0);
carryout: out std_logic
);
end entity;
architecture foo of alu_16_bit is
component alu_1_bit is
port (
a: in std_logic;
b: in std_logic;
ainvert: in std_logic;
binvert: in std_logic;
carryin: in std_logic;
operation: in std_logic_vector (1 downto 0);
result: out std_logic;
carryout: out std_logic
);
end component;
component controlcircuit is
port (
opcode: in std_logic_vector(2 downto 0);
ainvert: out std_logic;
binvert: out std_logic;
operation: out std_logic_vector(1 downto 0);
carryin: out std_logic -- invert a or b, add + 1 for subtract
);
end component;
signal ainvert: std_logic;
signal binvert: std_logic;
signal operation: std_logic_vector (1 downto 0);
signal carry: std_logic_vector (16 downto 0);
begin
CONTROL_CIRCUIT:
controlcircuit
port map (
opcode => opcode,
ainvert => ainvert,
binvert => binvert,
operation => operation,
carryin => carry(0) -- for + 1 durring subtract
);
GEN_ALU:
for i in 0 to 15 generate
ALU:
alu_1_bit
port map (
a => a(i),
b => b(i),
ainvert => ainvert,
binvert => binvert,
carryin => carry(i),
operation => operation,
result => result(i),
carryout => carry(i + 1)
);
end generate;
carryout <= carry(16) when operation = "10" else '0';
end architecture;
This represents moving ControlCircuit out of structural - only one copy is needed, renaming structural alu_1_bit and making the ports match.
There's a new top level alu_16_bit containing a single instance of ControlCircuit along with sixteen instances of alu_1_bit elaborated from the generate statement using the generate parameter i to index into arrays values for connections.
This design has been behaviorally implemented independently using the Opcode table you provided the link to:
as well as an independent fulladder used in alu_1_bit and appears functional.
This implies your design units haven't been validated.
i want to initialize my vectors from "0001" instead of "0000" default cause i'm doing an "automatic" 4 Bit multiplier and (x * 0) isn't useful, so
I want to skip the "0000" value.
Here is my Entity:
ENTITY multiplier IS
PORT (
clk, rst : IN std_logic;
q, r : INOUT std_logic_vector (3 DOWNTO 0) := "0001"; -- this not work
f : OUT std_logic_vector(7 DOWNTO 0)
);
END multiplier;
Use intermediate signals
library ieee;
use ieee.std_logic_1164.all;
entity multiplier IS
port (
clk : in std_logic;
rst : in std_logic;
q : out std_logic_vector(3 downto 0);
r : out std_logic_vector(3 downto 0);
f : out std_logic_vector(7 downto 0)
);
end entity;
architecture rtl of multiplier is
use ieee.numeric_std.all;
signal q_temp: unsigned(3 downto 0) := "0001"; -- or signed
signal r_temp: unsigned(3 downto 0) := "0001"; -- or signed
begin
[...your code...]
q <= std_logic_vector(q_temp);
r <= std_logic_vector(r_temp);
end architecture;
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_arith.all;
use ieee.numeric_bit.all;
use ieee.numeric_std.all;
entity multiplexer is
port (
A,B: in std_logic_vector (7 downto 0);
CI: in std_logic;
CO: out std_logic;
ANS: out std_logic_vector (7 downto 0);
OP: in std_logic_vector(1 downto 0);
EN: in std_logic);
end multiplexer;
architecture archi of multiplexer is
signal tmp: std_logic_vector (8 downto 0);
begin
process (EN) begin
if (EN = '1') Then
case OP is
when "00" =>
tmp <= conv_std_logic_vector((conv_integer(A)+conv_integer(B)+conv_integer(CI)),9);
ANS<= tmp(7 downto 0);
CO <= tmp(8);
when "01" =>
tmp <= conv_std_logic_vector((conv_integer(A)-conv_integer(B)+conv_integer(CI)),9);
ANS<= tmp(7 downto 0);
CO <= tmp(8);
when others => NULL;
end case;
else
NULL;
end if;
end process;
end archi;
error is coming at line 19 No feasible entries for infix operator '=' also Type error resolving infix expression "=" as type std.STANDARD.BOOLEAN. Where am I going wrong?
wave output
Surely this:
EN: in std_logic_vector
should be this:
EN: in std_logic
Your error message is complaining that there is no "=" operator defined that can compare a std_logic_vector to a '1', which is a literal of type std_logic.
I'm writing something in VHDL about an essay and I'm facing a strange situation. I've written some components, simulated and tested them, and everything seems to works fine. However, when simulating the top entity, I'm getting zeros as a result! Please take a look at the following listings:
Top Entity:
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity foobar is
port ( data_i : in std_logic_vector(39 downto 0);
sum_12bit_o : out std_logic_vector(11 downto 0)
);
end foobar;
architecture Behavioral of foobar is
--Declare components
component four_10bit_word_adder is
port( --Input signals
a_byte_in: in std_logic_vector(9 downto 0);
b_byte_in: in std_logic_vector(9 downto 0);
c_byte_in: in std_logic_vector(9 downto 0);
d_byte_in: in std_logic_vector(9 downto 0);
cin: in std_logic;
--Output signals
val12bit_out: out std_logic_vector(11 downto 0)
);
end component;
-- Signal declaration
signal int: std_logic_vector(11 downto 0);
signal intdata: std_logic_vector(39 downto 0);
begin
intdata <= data_i; --DEBUG
U1: four_10bit_word_adder port map (intdata(39 downto 30), intdata(29 downto 20),
intdata(19 downto 10), intdata(9 downto 0),
'0', int);
end Behavioral;
four_10bit_word_adder:
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity four_10bit_word_adder is
generic (
bits: integer := 10
);
port( --Input signals
a_byte_in: in std_logic_vector(bits-1 downto 0);
b_byte_in: in std_logic_vector(bits-1 downto 0);
c_byte_in: in std_logic_vector(bits-1 downto 0);
d_byte_in: in std_logic_vector(bits-1 downto 0);
cin: in std_logic;
--Output signals
val12bit_out: out std_logic_vector(bits+1 downto 0)
);
end four_10bit_word_adder;
architecture Behavioral of four_10bit_word_adder is
-- Component Declaration
component compressor_4_2 is
port(a,b,c,d,cin : in std_logic;
cout, sum, carry : out std_logic
);
end component;
--------------------------------------------------------+
component generic_11bit_adder
port (
A: in std_logic_vector(10 downto 0); --Input A
B: in std_logic_vector(10 downto 0); --Input B
CI: in std_logic; --Carry in
O: out std_logic_vector(10 downto 0); --Sum
CO: out std_logic --Carry Out
);
end component;
--------------------------------------------------------+
-- Declare internal signals
signal int: std_logic_vector(bits-1 downto 0); -- int(8) is the final Cout signal
signal byte_out: std_logic_vector(bits-1 downto 0);
signal carry: std_logic_vector(bits-1 downto 0);
signal int11bit: std_logic_vector(bits downto 0);
-- The following signals are necessary to produce concatenated inputs for the 10-bit adder.
-- See the paper for more info.
signal Concat_A: std_logic_vector(bits downto 0);
signal Concat_B: std_logic_vector(bits downto 0);
signal co : std_logic;
begin
A0: compressor_4_2 port map (a_byte_in(0), b_byte_in(0),
c_byte_in(0), d_byte_in(0),
'0', int(0), byte_out(0), carry(0));
instances: for i in 1 to bits-1 generate
A: compressor_4_2 port map (a_byte_in(i), b_byte_in(i),
c_byte_in(i), d_byte_in(i), int(i-1),
int(i), byte_out(i), carry(i));
end generate;
R9: generic_11bit_adder port map (Concat_A, Concat_B, '0', int11bit, co);
Concat_A <= int(8) & byte_out;
Concat_B <= carry & '0';
process (co)
begin
if (co = '1') then
val12bit_out <= '1' & int11bit;
else
val12bit_out <= '0' & int11bit;
end if;
end process;
end Behavioral;
4:2 Compressor
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity compressor_4_2 is
port(a,b,c,d,cin : in std_logic;
cout, sum, carry : out std_logic
);
end compressor_4_2;
architecture Behavioral of compressor_4_2 is
-- Internal Signal Definitions
signal stage_1: std_logic;
begin
stage_1 <= d XOR (b XOR c);
cout <= NOT((b NAND c) AND (b NAND d) AND (c NAND d));
sum <= (a XOR cin) XOR stage_1;
carry <= NOT((a NAND cin) AND (stage_1 NAND cin) AND (a NAND stage_1));
end Behavioral;
Generic 11-bit Adder:
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity generic_11bit_adder is
generic (
bits: integer := 11
);
port (
A: in std_logic_vector(bits-1 downto 0);
B: in std_logic_vector(bits-1 downto 0);
CI: in std_logic;
O: out std_logic_vector(bits-1 downto 0);
CO: out std_logic
);
end entity generic_11bit_adder;
architecture Behavioral of generic_11bit_adder is
begin
process(A,B,CI)
variable sum: integer;
-- Note: we have one bit more to store carry out value.
variable sum_vector: std_logic_vector(bits downto 0);
begin
-- Compute our integral sum, by converting all operands into integers.
sum := conv_integer(A) + conv_integer(B) + conv_integer(CI);
-- Now, convert back the integral sum into a std_logic_vector, of size bits+1
sum_vector := conv_std_logic_vector(sum, bits+1);
-- Assign outputs
O <= sum_vector(bits-1 downto 0);
CO <= sum_vector(bits); -- Carry is the most significant bit
end process;
end Behavioral;
I've tried a ton of things, but without any success. Do you have any idea what am I doing wrong? Sorry for the long question and thank you for your time.
Take a look at your process to generate val12bit_out in your four_10bit_word_adder entity. It's missing an input.
Also, there are several other issues. Fixing this one issue will not fix everything. But once you fix it, I think things will be a lot more clear.