CX is known as the count register, as the ECX, CX registers store the loop count in iterative operations . DX is known as the data register. It is also used in input/output operations. It is also used with AX register along with DX for multiply and divide operations involving large values.
What are the functions of SI and DI registers?
When you are using instructions like movsb, si is considered as the source register, while di is considered as the destination register . But they are both normal x86 registers. My assembly is a bit rusty, but one’s the Source Index, the other the Destination Index.
What are the main functions of the registers AX BX CX and DX?
BX – base register, typically used to hold the address of a procedure or variable . CX – count register, typically used for looping. DX – data register, typically used for multiplication and division.
What is the function of DX register?
DX – This is the data register. It is of 16 bits and is divided into two 8-bit registers DH and DL to also perform 8-bit instructions. It is used in multiplication an input/output port addressing .
Which 16 bit register has a special role in a multiplication operation?
Stack Pointer (SP): It is a 16-bit special purpose register which always stores the address of top of the Stack. i.e. it always points to top of the Stack. Stack is a part of the memory location used to store the data temporarily.
Which is type of general purpose register?
The general purpose registers are divided into two categories. Four registers, AX, BX, CX, and DX, are classified as data registers .
What are the functions of the four registers?
- Program counter (PC): Contains the address of an instruction to be fetched.
- Instruction register (IR): Contains the instruction most recently fetched.
- Memory address registers (MAR): Contains the address of a location in memory.
Is accumulator a special purpose register?
Special Purpose Registers. ... An accumulator is a register for short-term, intermediate storage of arithmetic and logic data in a computer’s CPU (Central Processing Unit). In an arithmetic operation involving two operands, one operand has to be in this register.
Which is special purpose register?
A Special Function Register (or Special Purpose Register, or simply Special Register) is a register within a microprocessor , which controls or monitors various aspects of the microprocessor’s function.
What are the types of registers?
- MAR Register. The full form of MAR is the memory address register. ...
- MDR. The full form of MDR register is a memory data register. ...
- MBR. The full form of MBR is the memory buffer register. ...
- PC. The full form of PC is the program counter register. ...
- Accumulator. ...
- Index Register. ...
- Instruction Register.
What is EBP register used for?
the EBP register pointers to the base. normally the only data item accessed in the stack is the one that is at the top of the stack. Although the EBP register is often used to mark a fixed point in the stack other than the top of the stack , for example of such data are the parameters.
What is EAX register used for?
EAX,AX,AH,AL : Called the Accumulator register. It is used for I/O port access, arithmetic, interrupt calls, etc ...
What is 32 bit register?
Most computers made in the 1990s and early 2000s were 32-bit machines. The CPU register stores memory addresses , which is how the processor accesses data from RAM. One bit in the register can reference an individual byte in memory, so a 32-bit system can address a maximum of 4 GB (4,294,967,296 bytes) of RAM.
What are the special purpose registers in 8086?
There are two special purpose registers on the 8086, i.e. the instruction pointer (ip) and the flag register . The ip is sometimes referred to as the pc (program counter). These registers cannot be accessed directly, rather, they are modified by the cpu during execution.
How accumulator is different from other registers?
The characteristic which distinguishes one register as being the accumulator of a computer architecture is that the accumulator (if the architecture were to have one) would be used as an implicit operand for arithmetic instructions .
Is accumulator a 16-bit register?
All microprocessors make use of an accumulator register that can supply one number for an action, and where the result of an action will also be stored. The size of the accumulator in terms of bits is used as a measure of the data unit capability of the microprocessor (as 8-bit, 16-bit, 32-bit, 64-bit, and so on).
