VHDL AND operator usage " no function declarations for operator "and""

Question

I have the following code:

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.NUMERIC_STD.ALL;
USE IEEE.STD_LOGIC_MISC.ALL;

ENTITY hazard_unit_forwards IS
    PORT (
        i_Rs1E, i_Rs2E : IN STD_LOGIC_VECTOR(4 downto 0);
        i_RdM, i_RdW : IN STD_LOGIC_VECTOR(4 downto 0);
        i_RegWriteM, i_RegWriteW : IN STD_LOGIC;
        o_ForwardAE, o_ForwardBE : OUT STD_LOGIC_VECTOR(1 downto 0)         -- forward A and B to execute stage
    );
END;

ARCHITECTURE behave OF hazard_unit_forwards IS

BEGIN
    -- forwarding logic for Rs1E
    PROCESS(i_Rs1E, i_RdM, i_RdW, i_RegWriteM, i_RegWriteW) BEGIN
        IF(((i_Rs1E = i_RdM) AND i_RegWriteM) AND (i_Rs1E /= "00000")) THEN     -- forward from memory stage
            o_ForwardAE <= "10";
        ELSIF (((i_Rs1E = i_RdW) AND i_RegWriteW) AND (i_Rs1E /= "00000")) THEN -- forward from writeback stage
            o_ForwardAE <= "01";
        ELSE                -- no forwarding (use RF output)
            o_ForwardAE <= "00";
        END IF;
    END PROCESS;
    
    -- forwarding logic for Rs2E
    PROCESS(i_Rs2E, i_RdM, i_RdW, i_RegWriteM, i_RegWriteW) BEGIN
        IF(((i_Rs2E = i_RdM) AND i_RegWriteM) AND (i_Rs2E /= "00000")) THEN     -- forward from memory stage
            o_ForwardBE <= "10";
        ELSIF (((i_Rs2E = i_RdW) AND i_RegWriteW) AND (i_Rs2E /= "00000")) THEN -- forward from writeback stage
            o_ForwardBE <= "01";
        ELSE                -- no forwarding (use RF output)
            o_ForwardBE <= "00";
        END IF;
    END PROCESS;
END;

VHDL types is giving me a PTSD, and I am sure it's the problem with types, but can't figure out what is wrong.

GHDL gives me the following errors:

hazard_unit_forwards.vhd:20:37:error: no function declarations for operator "and"
hazard_unit_forwards.vhd:22:41:error: no function declarations for operator "and"
hazard_unit_forwards.vhd:31:37:error: no function declarations for operator "and"
hazard_unit_forwards.vhd:33:41:error: no function declarations for operator "and"

So, what is wrong?

(the lines are basically everywhere AND operator is used in the code)

Answer 1

you can change If statement like this:

 (((i_Rs1E = i_RdM) AND (i_RegWriteM = '1') AND (i_Rs1E /= "00000"))

i hope that this will work for you.