Short Note on Two Pass Assembler
Two Pass Assembler :- In a two pass assembler , the fast pass as only to define the symbol and the second pass can them generate the instruction and addresses. The general task of two pass assembler are as follows –
a) Pass – 1 :-
Purpose : Define symbol and literals.
Activity :
i. Determine the length of the machine instruction.
ii. Track of location counter.
iii. Remember values of symbols until pass – 2
iv. Process sum pseudo operation.
v. Remember literals.
b) Pass – 2 :-
Purpose : Generate object program.
Activity :
i. Look up value of symbols .
ii. Generate Instructions.
iii. Generate data.
iv. Process pseudo operations.
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