How the address of data is obtained in index addressing mode?
2) Index Mode The address of the operand is obtained by adding to the contents of the general register (called index register) a constant value. The content of the instruction code, represents the starting address of the array and the value of the index register, and the index value of the current element.
Which instruction is the example of indexed addressing mode?
Indexed addressing mode The destination operand is always the register A. These are some examples of Indexed addressing mode. MOVCA, @A+PC; MOVCA, @A+DPTR; The C in MOVC instruction refers to code byte.
What is mean by index value in indexed addressing mode?
index value is the offset provided to the base address . the basic kind of indexed addressing as explained in Carl hamacher book is the X(Ri) which is used in the code snippet. X is a fixed offset that is R0 + 4 bytes , this offset cant be changed.
What is index addressing mode with example?
In index addressing mode, contents of Index register is added to address part of instruction to obtain effective address. The address part of instruction holds the beginning/base address and is called as base. The index register hold the index value, which is +ve. Base remains same, the index changes.
WHAT IS A indexed addressing explain with an example?
Indexed addressing mode: The operand’s offset is the sum of the content of an index register SI or DI and an 8 bit or 16 bit displacement. Example:MOV AX, [SI +05] Based Indexed Addressing: The operand’s offset is sum of the content of a base register BX or BP and an index register SI or DI. Example: ADD AX, [BX+SI]
What is the purpose of index register?
An index register in a computer’s CPU is a processor register or assigned memory location used for modifying operand addresses during the run of a program. This proved useful for doing vector/array operations and in commercial data processing for navigating from field to field within records.
What are the types of index register?
Index Register The index registers a type of processor register in the central processing unit (CPU) that is widely used for altering the address of operand at the time of program execution. The index register is widely used for doing array or vector operations.
What can the index register hold?
An index register is a circuit that receives, stores, and outputs instruction-changing codes in a computer. This circuit is also called an address register or a register of modifications. A register is a data-holding place in a computer processor.
What is source index?
Source index is use as a pointer to the current character being read in a string instruction(LODS,MOVS, or CMPS). Source index is also available as an offset to add Bx or Bp when doing indirect addressing. example: MOV [Bx + SI] , Ax.
What are the examples of index?
An example of index is to put employees names in alphabetical order. An example of index is to adjust wages based on the cost of living. The definition of an index is a guide, list or sign, or a number used to measure change. An example of an index is a list of employee names, addresses and phone numbers.
What are pointers and index register?
The pointer registers contain the offset within a particular segment. The BP & SP registers holds the offsets within the data and stack segments respectively. The Index registers are used as general purpose registers as well as for holding the offset in case of indexed based and relative indexed addressing modes.
Which register is memory pointer?
Stack registers in x86 In 8086, the main stack register is called stack pointer – SP. The stack segment register (SS) is usually used to store information about the memory segment that stores the call stack of currently executed program.
Which is not a visible register?
Explanation: MAR or the memory address register is not a visible register. It contains the address of the memory block to be read or written to.
Is are memory pointer register S?
Program Counter: This register is used to sequence the execution of the instructions. The function of the program counter is to point to the memory address from which the next byte is to be fetched. Stack Pointer: It is used as a memory pointer. It points to a memory location in read/write memory, called the stack.