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System Software - December 2014
VTU Computer Science (Semester 5)
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary
1(a) Distinguish between system software and application software.
4 marks
1(b) Explain SIC/XE architecture. 4 marks
1(c) Wirte a SIC/XE program to copy array A of 100 words to array B of same size. 4 marks
1(d) What is upward compatible? How is it ensured between SIC and SIC/XE? 4 marks
2(a) Explain briefly the SIC assembler directives with examples. 4 marks
2(b) What a relocation? Illustrate how a modification record is used in relocation of program. 4 marks
2(c) Generate the machine codes for the following SIC/XE program.
copy | START | 1000 |
CLOOP | +JSUB | RDREC |
LDA | LENGTH | |
COMP | ZERO | |
JEQ | EXIT | |
J | CLOOR | |
EXIT | STA | BUFFER |
LDA | THREE | |
STA | TOTAL-LENGTH | |
RSUB | ||
BUFFER | RESW | 100 |
EOF | BYTE | C'EOF' |
ZERO | WORD | 0 |
THREE | WORD | 3 |
LENGTH | RESW | 1 |
TOTAL-LENGTH | RESW | 1 |
RDRES | LDX | ZERO |
MNEMONICS:
JSUB = A0, LDA = 80, LDX = 60,STA = 50,
COMP = 90, RSUB = 4C, JEQ = B0, J = B8 4 marks
3(a) What is a literal? Differentiate literals form immediate data. 4 marks
3(b) Explain the following machine independent features of SIC assembler.
i) Symbol defining statements
ii) Control sections
4 marks
3(c) Explain the two design options of one-pass assembler. 4 marks
4(a) Write the algorithm of absolute loader. 4 marks
4(b) Write the algorithm of linking loader. 4 marks
4(c) Explain briefly the design options of loaders. 4 marks
5(a) List the basic tasks of a text editor. 4 marks
5(b) With a neat diagram, explain the text editor structure. 4 marks
5(c) List the user interfaces for editors with an example for each. 4 marks
5(d) What are the debugging functions and capabilities? 4 marks
6(a) Give the feature of MACROPROCESSORS and explain the data structures use in macro processors. 4 marks
6(b) Explain any two facilities provided for implementing interacting process in programming language and operating system. 4 marks
6(c) For the following macro definition,expand the macro call statements called in sequence:
i) RDBUFF F1, BUFA, RLEN,04 1024
ii) RDBUFF F2, BUFB, RLNG,
RDBUFF MACRO & INDEV, &BUFADE, &RECLTH, &EOR, &MAXLTH
IF (&EORNE ' ')
&EORCR | SET | 1 |
ENDIF | ||
CLEAR | X | |
CLEAR | A | |
IF | (&EORCR EQ1) | |
LDCH | =X '&EOR' | |
RMO | A,S | |
ENDIF | ||
IF | (&MAXLTH EQ ' ') | |
+LDT |
4096 |
|
ELSE | ||
+LDT | =#MAXLTH | |
ENDIF | ||
$LOOP\lt/td\gt \lttd\gt TD\lt/td\gt \lttd\gt =X '&INDEV'\lt/td\gt \lt/tr\gt \lttr\gt \lttd\gt \lt/td\gt \lttd\gt JEQ\lt/td\gt \lttd\gt $LOOP | ||
RD | =X '&INDEV' | |
STCH | &BUFADR, X | |
TIXR | T | |
JLT | $LOOP | |
STX | &RECLTH | |
MEND |
7(a) List any ten regular expression in lex. 4 marks
7(b) Distinguish between LEXER and Handwritten lexer. 4 marks
7(C) Write lex program to compute word, character and line count in a given file. 4 marks
8(a) Explain the format of yacc program. 4 marks
8(b) Write lex-yacc program to validate simple arithmetic expression. 4 marks
8(c) Explain briefly lex and yacc interaction. 4 marks
8(d) Discuss conflicts in yacc 4 marks