If CS = 135Ch, IP = 0100h, after a nop (machine code 90h) instruction. (a) CS =
ID: 3825809 • Letter: I
Question
If CS = 135Ch, IP = 0100h, after a nop (machine code 90h) instruction. (a) CS = 135Ch (b) CS = 135Dh (c) IP = 0100h (d) IP = 0101h If CS = 135Ch, IP = 0100h, after a loop 0105h (machine code E203h) instruction, which one of the following is true? (a) IP = 0102h (b) IP = 0105h (c) IP = 0102h or 0105h d) IP could be something else After _____, both CS and IP could be changed. (a) imp near ptr here; here is a label in the same segment (b) call dword ptr [SI] (c) call BX (d) hardware interrupt For a software interrupt int nn instruction, which of the following is UNTRUE? (a) The number nn alone determines the physical address for the interrupt vector table entry. (b) If interrupt is disabled (IF = 0), the interrupt will be ignored. (c) The interrupt service routine starts at the address in the interrupt vector table. (d) The interrupt service routine ends with an IRET instruction.Explanation / Answer
If CS = 135Ch, IP = 0100h, after a nop instruction:
nop simply means no operation. And therefore, will not affect the CS, and IP will
point to the next instruction therefore, the answer is:
a. CS = 135Ch, and d. IP = 0101h
If CS = 135h, IP = 0100h, after a loop 0105h instruction:
The loop instruction just makes the control jump to specified label/address.
So, loop 0105h, will just make the IP contain 0105h.
So, the answer is: b. IP = 0105h.
After ___, both CS and IP could be changed.
The CS is the CodeSegment register and is changed only when the segment in which the code
to be executed is changed, so, (a) jmp near ptr here; will not do the thing, as the label
is in the same segment.
A CALL will move from one code segment to another code segment,
So, the answer is:
b. call dword ptr[SI]
c. call BX.
For a software interrupt int nn instruction, which of the following is untrue?
(a). The number nn alone determines the physical address for the interrupt table entry.