Visvesvaraya Technological University (VTU) 2007 B.E Computer Science system software - Question Paper

PART-A
1 a. Bring out the differences ranging from Application software and System software.
b. discuss SIC/XE machine instruction formats and all addressing modes clearly indicating the setting of various flag bits.
c. Write a subroutine in SIC/XE to learn a 100-byte record from a device 'F5' into buffer.
Use immediate and register-to register instructions.

2 a. Write and discuss the algorithm of pass-1 of a 2 pass assembler.
b. Generate the complete object program for the subsequent assembly level program.
SUM START 0
FIRST CLEAR X
LDA #0
+LDB #TOTAL
BASE TOTAL
LOOP ADD TABLE,X
TIX COUNT
JLT LOOP
STA TOTAL
COUNT RESW 1
TABLE RESW 2000
TOTAL RESW 1
END FIRST
Assume beneath opcodes(all in hexadecimal)
CLEAR-B4 LDA-00 LDB-68 ADD-18
TIX-2C JLT-38 STA-0C

3 a. Distinguish ranging from literal and an immediate operands. How does the assembler handle the literal operand?
b. Compare a two-pass assembler with a 1 pass assembler.How forward references are
handled in 1 pass assembler?
c. Write a note on MASM assembler.

4 a. provide and discuss the algorithm or source program for a simple bootstrap loader.
b. Distinguish ranging from linking loader and linkage editors.
c. discuss dynamic linking with suitable diagrams.

PART-B
5 a. discuss the structure of a text editor with a neat diagram.
b. discuss the functions and capabilities of an interactive debugging system.
c. Write a note on the aspect of the user-interface criteria.

6 a. elaborate the basic functions of a macroprocessor? discuss the different data structures
used in the implementation of one-pass macroprocessor.
b. Using the subsequent definition, expand the subsequent macro calls, called in sequence.
i) tag RDBUFF F2, BUFFER, LENGTH, (04,12)
ii) RDBUFF OE, BUFF, RLENG, , 2048
RDBUFF MACRO &INDEV, &BUFADR,&RECLTH, &EOR, &MAXLTH
&EORCT SET %NITEMS(&EOR)
CLEAR X
CLEAR A
IF (&MAXLTH EQ ' ')
+LDT #4096
ELSE
+LDT #&MAXLTH
ENDIF
$LOOP TD =X '&INDEV'
JEQ $LOOP
RD =X'&INDEV'
&CTR SET 1
WHILE (&CTR LE &EORCT)
COMP =X '0000 &EOR[&CTR]'
JEQ $EXIT
&CTR SET &CTR+1
ENDW
STCH &BUFADR,X
TIXR T
JLT $LOOP
$EXIT STX &RECLTH
MEND

c. Write a short note on 'keyword macro parameters'.

7 a.List and discuss the various design choices for a macro processor.
b.Write a short note on 'parser - lexer communication'.
c. Write a LEX program to count the number of vowels and consonants in a provided string.

8 a.Explain regular expressions in UNIX with proper examples.
b.Explain the structure of YACC program.
c. provide the LEX and YACC specifications to recognise parenthtsized arithmatic expressions.

Earning:   Approval pending.