Explanation: The stack pointer(SP) is an 8-bit register and is initialized to internal RAM address
07H after reset
.
What is the default value of stack pointer of 8051?
The stack pointer in the 8051 is 8-bits wide, and it can take a value of
00 to FFH
. When the 8051 is initialized, the SP register contains the value 07H. This means that the RAM location 08 is the first location used for the stack.
What is the value of stack pointer?
The stack pointer (SP) points to the top element of the stack. The current value of SP is
(016E)hex
. The CALL instruction is of two words, the first word is the op-code and second word is the starting address of the subroutine (one word = 2 Bytes).
What will be the address of stack pointer after reset?
After reset, the stack pointer is initialized to
7h
. The stack will start growing up from address 8h.
What is the default value of stack pointer sp )?
Stack registers in x86
SP points to current stack top. By default,
the stack grows downward in memory
, so newer values are placed at lower memory addresses. To push a value to the stack, the PUSH instruction is used. To pop a value from the stack, the POP instruction is used.
Why stack pointer is required?
The Stack Pointer (SP) register is
used to indicate the location of the last item put onto the stack
. When you PUT something ONTO the stack (PUSH onto the stack), the SP is decremented before the item is placed on the stack.
What is stack pointer for?
A stack pointer is a small register
that stores the address of the last program request in a stack
. … When a new data item is entered or “pushed” onto the top of a stack, the stack pointer increments to the next physical memory address, and the new item is copied to that address.
What is initial value of stack pointer after reset?
Stack pointer (SP) is a 8 bit wide register and is incremented before the data is stored into the stack using PUSH or CALL instructions. … After reset, the SP register is initialized to
07
.
What are issues with stack and bank 1?
What are issues related to stack and bank 1.
Bank 1 uses the same RAM space as the stack. Stack pointer is incremented or decremented according to the push or pop instruction
. … The push instruction may also take stack to location 0 i.e.it will run out of space.
What is DPTR in 8051?
The
Data Pointer
(DPTR) is the 8051’s only user-accessible 16-bit (2-byte) register. … It is used by the 8051 to access external memory using the address indicated by DPTR. DPTR is the only 16-bit register available and is often used to store 2-byte values.
How do you initialize a stack pointer?
To set up the stack pointers, enter each mode with interrupts disabled, and assign the appropriate value to the stack pointer. The stack pointer value set up in the reset handler is automatically passed as a parameter to
__user_initial_stackheap()
by C library initialization code.
What is the difference between stack pointer and program counter?
The main difference between stack pointer and program counter is that
the stack pointer is a register that stores the address of the last program request in a stack
while the program counter is a register that stores the address of the next instruction to be executed from the memory.
What is stack example?
There are many real-life examples of a stack. Consider an example of
plates stacked over one another in the canteen
. The plate which is at the top is the first one to be removed, i.e. the plate which has been placed at the bottommost position remains in the stack for the longest period of time.
What can be the maximum value held by stack pointer in pic18?
The pointer is only five-bits wide, which accounts for a stack depth of 32 words. However, the first location is not counted, since it is not physically a memory location in the stack. The first location always contains the value
000000h
, which means there are only 31 usable locations in the stack.
What is CPU stack?
The stack is
a list of data words
. It uses Last In First Out (LIFO) access method which is the most popular access method in most of the CPU. A register is used to store the address of the topmost element of the stack which is known as Stack pointer (SP). … After manipulation, the result is placed in the stack.
What is the size of stack pointer?
There is a stack pointer and a instruction pointer, the stack pointer having 8 explicit and 8 implicit bits (stack is always in the same
256-byte
region) and thus the stack pointer register having 8 bits, the instruction pointer having 16 bits. The 8086, has an 16 bit databus and a 20 bit addressbus.
