Where is == operator defined in Class “object”?

Question

I searched the source code of FCL, and I got confused that string.Equals() uses Object.ReferenceEquals(), and Object.ReferenceEquals() use

Answer 1

ceq takes two values from the stack and gives results. If the result value is 1 then they are considered equal and 0 if they are not equal.

However, the == operator doesn't always get translated to ceq. Whether == in C# results in ceq depends on some more factors like are data types primitives or do they have custom == operators or are they references.