Which is special purpose register in 80386?
The three special registers, namely Control registers CR0-CR3, Debug Register DR0-DR7 & Test Register TR6-TR7, are defined briefly in this context.
What are the different registers of 80386?
The six segment registers available in 80386 are CS, SS, DS, ES, FS and GS. The CS and SS are the code and the stack segment registers respectively, while DS, ES, FS, GS are 4 data segment registers. A 16 bit instruction pointer IP is available along with 32 bit counterpart EIP.
What is a register a special type of?
A special purpose register is one that has a specific control or data handling task to carry out. There are a number of special purpose registers within the CPU. The diagram above shows that the CPU contains a number of registers in order to process data and to follow program instructions.
What are the 2 special purpose registers?
Special purpose registers ( SPR ) hold program state; they usually include the program counter (aka instruction pointer), stack pointer, and status register (aka processor status word).
What are the features of 80386?
Features of 80386
- As it is a 32-bit microprocessor.
- 80386 has a data bus of 32-bit.
- It holds an address bus of 32 bit.
- It supports physical memory addressability of 4 GB and virtual memory addressability of 64 TB.
- 80386 supports a variety of operating clock frequencies, which are 16 MHz, 20 MHz, 25 MHz, and 33 MHz.
Which register is used in virtual 86 mode?
The CPU is executing in virtual 86 mode when the VM bit (bit 17) is set in the EFLAGS register. If you want to enter virtual 86 mode you must set this bit to 1.
What is the use of AX register?
AX is the primary accumulator; it is used in input/output and most arithmetic instructions. For example, in multiplication operation, one operand is stored in EAX or AX or AL register according to the size of the operand. BX is known as the base register, as it could be used in indexed addressing.
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.
What are types of registers?
There are different types of Registers that are used. Some of the most used Registers are accumulator, data register, address register, program counter, memory data register, index register, and memory buffer register. The various operations are performed with the use of register.
Is accumulator a special purpose register?
What is the purpose of IP registers?
A special-purpose register, usually called the instruction pointer (IP) or program counter (PC), keeps track of what instruction is being executed.
What are the three working modes of 80386?
The 80386 has three processing modes: Protected Mode. Real-Address Mode. Virtual 8086 Mode.
What are the registers in 80386 16 bit?
BP, SP, SI, DI represents the lower 16 bit of their 32 bit counterparts, and can be used as independent 16 bit registers. The six segment registers available in 80386 are CS, SS, DS, ES, FS and GS. The CS and SS are the code and the stack segment registers respectively, while DS, ES, FS, GS are 4 data segment registers.
What are the special purpose registers on the 80386?
Status and instruction registers. These special-purpose registers are used to record and alter certain aspects of the 80386 processor state. 2.3.1 General Registers The general registers of the 80386 are the 32-bit registers EAX, EBX, ECX, EDX, EBP, ESP, ESI, and EDI.
What do the flags do on the 80386?
The flags control certain operations and indicate the status of the 80386. The low-order 16 bits of EFLAGS is named FLAGS and can be treated as a unit. This feature is useful when executing 8086 and 80286 code, because this part of EFLAGS is identical to the FLAGS register of the 8086 and the 80286.
Which is the lower 16 bit register EAX?
AX represents the lower 16 bit of the 32 bit register EAX. BP, SP, SI, DI represents the lower 16 bit of their 32 bit counterparts, and can be used as independent 16 bit registers. The six segment registers available in 80386 are CS, SS, DS, ES, FS and GS.