What are the different control registers in 80386?

What are the different control registers in 80386?

Four registers of the 80386 locate the data structures that control segmented memory management: GDTR Global Descriptor Table Register. LDTR Local Descriptor Table Register. IDTR Interrupt Descriptor Table Register.

What is control register in 80386 microprocessor?

3 Control Registers. Figure 4-2 shows the format of the 80386 control registers CR0, CR2, and CR3. These registers are accessible to systems programmers only via variants of the MOV instruction, which allow them to be loaded from or stored in general registers; for example: MOV EAX, CR0 MOV CR3, EBX.

Which is the 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 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.

What are general purpose registers?

General purpose registers are used to store temporary data within the microprocessor. It is of 16 bits and is divided into two 8-bit registers BH and BL to also perform 8-bit instructions. It is used to store the value of the offset. Example: MOV BL, [500] (BL = 500H) CX – This is the counter register.

Is a 16 bit register of 80386 processor?

Signal Descriptions of 80386. The 80386 has eight 32 – bit general purpose registers which may be used as either 8 bit or 16 bit registers. A 32 – bit register known as an extended register, is represented by the register name with prefix E. AX represents the lower 16 bit of the 32 bit register EAX.

What is the function of flag register?

The Flag register is a Special Purpose Register. Depending upon the value of result after any arithmetic and logical operation the flag bits become set (1) or reset (0). In 8085 microprocessor, flag register consists of 8 bits and only 5 of them are useful.

How many registers are there in 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 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 flags of the 80386 microprocessor?

Out of the 32 bits, Intel has reserved bits D18 to D31, D5 and D3, while D1 is always set at 1.Two extra new flags are added to the 80286 flag to derive the flag register of 80386. They are VM and RF flags. •VM – Virtual Mode Flag: If this flag is set, the 80386 enters the virtual 8086 mode within the protection mode.

When did the Intel 80386 microprocessor come out?

The Intel 80386, also known as i386 or just 386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistors and were the CPU of many workstations and high-end personal computers of the time. As the original implementation of the 32-bit extension of the 80286 architecture,…

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.