IMPLEMENTATION OF
SINGLE PASS ASSEMBLER
AIM
To implement single pass assembler using C.
ALGORITHM
1.Read first line from the intermediate file.
2.Check to see if the opcode from the first line read is
“START”.If so then write label,opcode and operand field values of corresponding
statement directly to final output files.
3.Start the following processing for other lines in
intermediate file if it is not a comment line until an “END” statement is
reached.
4.Start writing labels LOCCTR opcode and operand fields of
corresponding statements to the output file along with the object code.The
object code is found by assembling each statement opcode machine equivalent
with the label address.
5.If there is no symbol or label in the operand field , then
the operand address is assigned as zero and it is assembled with object code of
instruction.
6.If OPCODE is BYTE,WORD,RESB etc are convert constants to
object code close operand file and exit.
