What is the Design of single pass assembler?

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. Advantages

Every source statement needs to be processed once.

Disadvantages

We cannot use any forward reference in our program. Forward Reference

Forward 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.