System Software : Question Paper Dec 2013 - Computer Science Engg. (Semester 5) | Visveswaraya Technological University (VTU)

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System Software - Dec 2013

Computer Science Engg. (Semester 5)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks. 1 (a) Bring out the differences between system software and application software.(4 marks) 1 (b) Write programs in both SIC and SIC/XE to copy a character string 'System Software' to another string.(6 marks) 1 (c) Explain the following with reference to SIC/XE machine architecture:
(i) Instruction formats
(ii) Addressing mode
(iii) Data formats
(iv) Register organization(10 marks) 2 (a) Explain the different data structures used in two pass assembler. Mention clearly their functins in Pass 1 and Pass 2.(6 marks) 2 (b) What is the need of pass 2 assembler? Reason out with a simple example.(4 marks) 2 (c) Generate the object code and complete object program for the following SIC/XE program.

SUM	START	0	OPCODES
FIRST	LDX	#0	LDX	-04
	LDA	#0	LDA	-00
	+LDB	#TABLE2	LDB	-68
	BSE	TABLE2	ADD	-18
LOOP	ADD	TABLE, X	TIX	-2C
	ADD	TABLE2, X	JLT	-38
	TIX	COUNT	STA	-OC
	JLT	LOOP	RSUB	-4C
	+STA	TOTAL
	RSUB
COUNT	RESW	1
TABLE	RESW	2000
TABLE	RESW	2000
TOTAL	RESW	1
	END	FIRST

(10 marks) 3 (a) With suitable example, explain the use of LTORG assembler directive.(4 marks) 3 (b) Differentiate between program blocks and control sections. Explain how control sections are processed.(8 marks) 3 (c) Discuss how forward reference are handled by multi-pass assembler. Show step by step procedure to evaluate the following statements. Show the symbol table after each scan.

1.	NUMB	EQU	MAXLEN/2
2.	MAXLEN	EQU	BEND-BUF
3.	PREVB	EQU	BUF-1
4.	BUF	RESB	4096
5.	BEND	EQU	*

Assume the value for location counter as 1034 (H) at line number 4.(8 marks) 4 (a) Explain with an algorithm the working of an absolute loader.(6 marks) 4 (b) Distinguish between linking loader and linking editor.(4 marks) 4 (c) What are the major data structures required for linkage loader? Write and explain the algorithm for pass 1 of linking loader.(10 marks) 5 (a) What is an interactive editor? List the four tasks performed by document linking process in an interactive system.(4 marks) 5 (b) Explain briefly structure of a typical editor with the help of a block daigram.(10 marks) 5 (c) Discuss briefly the following debugging functions:
(i) Break points
(ii) Tracing
(iii) Trace back(6 marks) 6 (a) Explain with an example the various data structure required for the design of a macro processor.(8 marks) 6 (b)

SUM	MACRO	&ID
	LDA	X&ID?1
	ADD	X&ID?2
	STA	X&ID?5
	MEND

Expand the following macro invocation statement using the above given macro:
(i) SUM BEETA (ii) SUM A(4 marks) 6 (c) Explain the advantages and disadvantages of general purpose macro processors.(8 marks) 7 (a) Explain with an example the structure of lex program(8 marks) 7 (b) Define regular expression. Give regular expression for the following
(i) · (ii) * (iii) ^ (iv) $ (v) {} (vi) ?(4 marks) 7 (c) Write a lex program to count the vowels and consonants in given string.(8 marks) 8 (a) What is shift/reduce parsing? Explain the parsing for the string "feed=12+13" using the following grammer.
Statement ? NAME= expression
Expression ? NUMBER + NUMBER / NUMBER-NUMBER(10 marks) 8 (b) Write a YACC program to recognize the validity of an arithmetic expression that uses +, -, * and /.(10 marks)

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