In assembly please 1.What is the effect of the following instructions executing

Question

In assembly please

1.What is the effect of the following instructions executing on a modern x86 64-bit system (describe what happens and the final contents of the registers involved)? Can you obtain the same end result using only two instructions, and no other registers?

PUSH RAX

PUSH RBX

PUSH RCX

XOR RAX,RAX

XOR RBX,RBX

XOR RCX,RCX

POP RAX

POP RAX

POP RBX

2. What is the purpose of a segment register in protected mode memory addressing?

3. For a 32-bit Pentium4 descriptor that contains a base address of 01000000H, a limit of 0FFFFH, and G=0, what starting and ending locations are addressed by it? (also see Segmentation and Pagination Diagrams in BlackBoard, Other Reference Materials).

4. If DS=0105H in protected mode, which descriptor entry, table, and RPL are selected? (also see Segmentation and Pagination Diagrams in BlackBoard, Other Reference Materials).

5. What is the purpose of the TLB located within the Pentium class microprocessor?

Explanation / Answer

2. What is the purpose of a segment register in protected mode memory addressing?

Answer:

The segment registers have a very special purpose - pointing at accessible blocks of memory. Segment registers work together with general purpose register to access any memory value

Protected Mode Memory Addressing. Segment register contains a selector that selects a descriptor from the descriptor table. The descriptor contains information about the segment, e.g., it's baseaddress, length and access rights.

5. What is the purpose of the TLB located within the Pentium class microprocessor?

Answer:

The TLB, or Translation Lookaside Buffer, is a hardware cache within the processor's bus interface unit that stores recently used copies of Page Table entries. This speeds up conversion from virtual address to physical address.

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