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System Software - Jun 2012
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) Explain the instruction formats and addressing modes of SIC/XE machine.(10 marks)
1 (b) Write a program in both SIC and SIC/XE to copy a character string 'system software' to another string.(10 marks)
2 (a) Explain the five fundamental functions of an SIC assembler.(5 marks)
2 (b) Explain the data structures used in assembler algorithms.(5 marks)
2 (c) Generate the object code for the each statement and write the object programs for the following SIC/XE program.
(Given that: LDX=04, LDA=00, LDB=68, ADD=18, TIX=2C, JLT=38, STA=OC, RESUB=4C).
| SUM | START | 0 |
| FIRST | LDX | #0 |
| LDA | #0 | |
| +LDB | # TABLE 2 | |
| BASE | TABLE 2 | |
| LOOP | ADD | TABLE, X |
| ADD | TABLE2, X | |
| TIX | COUNT | |
| JLT | LOOP | |
| +STA | TOTAL | |
| RSUB | ||
| COUNT | RESW | 1 |
| TABLE | RESW | 2000 |
| TABLE2 | RESW | 2000 |
| TOTAL | RESW | 1 |
| END | FIRST |
(i) [] (ii) {} (iii) / (iv) ()(8 marks) 8 (a) Define YACC tools. What are tow types of conflicts in YACC? Give examples.(10 marks) 8 (b) Write a YACC program to validate a simple arithmetic expression involving operators +, -, *, /.(10 marks)

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