When one pass assembler constructing the object code, if it finds usage of the variables before the declaration then forward reference problem will occur.
To avoid forward reference problem:
i) Declare the symbols before using it
ii) Use more than one pass assembler(multi pass assembler)
This answer is: 👍 Helpful ( 5 ) 👎 Not Helpful ( 4 ) Add a Comment More answersA forward reference occurs when a label is used as an operand, for example as a branch target, earlier in the code than the definition of the label. The assembler cannot know the address of the forward reference label until it reads the definition of the label.
Example of Forward Reference :
In above example a is used before declaration so it will create the problem of forward reference.
This answer is: 👍 Helpful ( 1 ) 👎 Not Helpful ( 0 ) Add a CommentPass1: assign addresses to all symbol
Pass2: generate object code in order to solve
the problem of forward reference
This answer is: 👍 Helpful ( 1 ) 👎 Not Helpful ( 2 ) Add a Comment
Single Pass Assembler A single pass assembler scans the program only once and creates the equivalent binary program. The assembler substitute all of the symbolic instruction with machine code in one pass. AdvantagesEvery source statement needs to be processed once.DisadvantagesWe cannot use any forward reference in our program. Forward ReferenceForward reference means; reference to an instruction which has not yet been encountered by the assembler. In order to handle forward reference, the program needs to be scanned twice. In other words a two pass assembler is needed.
One well known and good assembler is NASM. (Netwide ASseMbler). This can be found at http://nasm.sf.net
In an authenticated key-agreement protocol that uses public key cryptography, perfect forward secrecy (or PFS) is the property that ensures that a session key derived from a set of long-term public and private keys will not be compromised if one of the (long-term) private keys is compromised in the future. Forward secrecy has been used as a synonym for perfect forward secrecy [1], since the term perfect has been controversial in this context. However, at least one reference [2] distinguishes perfect forward secrecy from forward secrecy with the additional property that an agreed key will not be compromised even if agreed keys derived from the same long-term keying material in a subsequent run are compromised.
Yes. Port forwarding is typically done in the router. However, you cannot forward the same port to more than one computer on the network.
A SCR's (Silicon Controller Rectifier) name hints at the answer. As a rectifier (diode) current can only pass in one direction. There are devices at can pass in both directions, and typically they are a pair of SCR's wired in opposite polarity.
