Pass Structure of Assembler :

One complete scan of the source program is known as a pass of a Language Processor. Two types 1) Single Pass Assembler 2) Two Pass Assembler.

Single Pass Assembler :

€ First type to be developed

€ Most Primitive

€ Source code is processed only once.

The operand field of an instruction containing forward reference is left blank intially Eg) MOVER BREG,ONE

Can be only partially synthesized since ONE is a forward reference

€ During the scan of the source program, all the symbols will be stored in a table called SYMBOL TABLE. Symbol table consists of two important fields, they are symbol name and address.