Which register stores the address of the next data element to be stored onto the stack?

Which register stores the address of the next data element to be stored onto the stack?

• A. Extended Stack Pointer (ESP)
• B. Extended Base Pointer (EBP)
• C. Extended Instruction Pointer (EIP)
• D. Extended Source Index (ESI)

Answer: (A)

In x86, the stack pointer holds the address of the top of the stack—the location where the next push will place data. In 32-bit mode, when you push a value, the processor first decreases ESP and then writes the value to the memory address in ESP. That means ESP points to the next data element to be stored on the stack. The base pointer (EBP) is used to reference function parameters and local variables within a stack frame, not the next push location. The instruction pointer (EIP) tracks the address of the next instruction to execute. The source index (ESI) is a general-purpose index register often used for string or memory operations, not for tracking the stack top.

In x86, the stack pointer holds the address of the top of the stack—the location where the next push will place data. In 32-bit mode, when you push a value, the processor first decreases ESP and then writes the value to the memory address in ESP. That means ESP points to the next data element to be stored on the stack.

The base pointer (EBP) is used to reference function parameters and local variables within a stack frame, not the next push location. The instruction pointer (EIP) tracks the address of the next instruction to execute. The source index (ESI) is a general-purpose index register often used for string or memory operations, not for tracking the stack top.