Question

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1. Which index register is used by the STOSD instruction?

2. In what way is the CMPS instruction ambiguous?

3. Suppose a two-dimensional array of doublewords has three logical rows and four logical columns. Write an expression using ESI and EDI that address the third column in the second row. (Numbering for rows and columns starts at zero).

4. What is the maximum number of comparisons needed by the binary search algorithm when an array contains 1,024 elements?

Answer 1

1.
EDI

2.
The CMPS instruction is ambiguous because regardless of the operands used, it still compares the contents of memory pointed to by ESI to the memory pointed to by EDI. 

3.
mov esi, 2 ; row
mov edi, 3 ; column
mov eax ,[esi * 16 + edi * 4]

4.
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