Syntax in assignment statement l-value

Question

1. This is code

2. and can't recognize the error

3. it's showing new_content as error. I changed its name, but error are also showing

I thing this is a logical error

module IF_ID(new_content, instruction, newPC, clk, pwrite1);
input pwrite1, clk;
input [31:0] instruction, newPC;
output [63:0] new_content;
reg [63:0] next;
always (@negedge clk) begin
    if(pwrite1)
        new_content <= {instruction, newPC};
    else
        new_content <= 64'b0;

end

endmodule

I get these errors:

jdoodle.v:6: syntax error
jdoodle.v:8: Syntax in assignment statement l-value.
jdoodle.v:9: syntax error
jdoodle.v:10: error: invalid module item.
jdoodle.v:12: syntax error

Answer 1

You have 2 types of syntax errors.

You need to declare new_content as a reg since you make a procedural assignment to it in an always block.

You need to place @ to the left of the ( in your always line.

This code compiles with no errors for me:

module IF_ID(new_content, instruction, newPC, clk, pwrite1);
input pwrite1, clk;
input [31:0] instruction, newPC;
output reg [63:0] new_content;
reg [63:0] next;
always @(negedge clk) begin
    if(pwrite1)
        new_content <= {instruction, newPC};
    else
        new_content <= 64'b0;

end
endmodule