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What is GDTR in assembly language?
Global Descriptor Table Register (GDTR) The GDTR register holds the base address (32 bits in protected mode; 64 bits in IA-32e mode) and the 16-bit table. limit for the GDT. The base address specifies the linear address of byte 0 of the GDT; the table limit specifies the. number of bytes in the table.
What does GDTR and IDTR contain?
2 Answers. In sort: GDT and IDT: 32 or 64 bits (in protected and long mode respectively) base address + 16 bits limit = 48 bits LDT and TR: 16 bits, as every other segment register. You can also take a look at wiki.osdev.org, it is a wiki about Operating System development.
How big is GDTR?
GDTR. The GDT is pointed to by a special register in the x86 chip, the GDT Register, or simply the GDTR. The GDTR is 48 bits long. The lower 16 bits tell the size of the GDT, and the upper 32 bits tell the location of the GDT in memory.
What is GDTR LDTR IDTR?
The GDTR, LDTR, IDTR, and TR registers each have a load and store instruction for loading data into and storing. data from the register: • LGDT (Load GDTR Register) — Loads the GDT base address and limit from memory into the GDTR register.
Which instruction is used to load the GDTR?
lgdt/lidt instructions
Description. The GDTR and IDTR are loaded with a linear base address and limit value from a six-byte operand in memory by the lgdt/lidt instructions.
What is paging explain its implementation in 80386 microprocessor?
The Paging unit organizes the physical memory in terms of pages of 4kbytes size each. Paging unit works under the control of the segmentation unit, i.e. each segment is further divided into pages. The virtual memory is also organizes in terms of segments and pages by the memory management unit.
Which of the following instruction is used to load the GDTR?
Description. The GDTR and IDTR are loaded with a linear base address and limit value from a six-byte operand in memory by the lgdt/lidt instructions. For a 16-bit operand: Load the register with a 16-bit limit and a 24-bit base.
What is the maximum size of GDT?
65536 bytes
The size of the descriptor table is subtracted by 1 because 65535 is the maximum value for size but the GDT can only be up to 65536 bytes (which means that the entries can be maximum of 8192).
Where is the GDT stored?
memory
GDT is stored in memory. Its size and address is stored in the GDTR register. The GDTR register contains 48 bits: 16 bits for the size of the GDT and 32 bits for its address. Each descriptor stored in a GDT is 64 bits.
What is the size of GDT table?
The size of the descriptor table is subtracted by 1 because 65535 is the maximum value for size but the GDT can only be up to 65536 bytes (which means that the entries can be maximum of 8192).
What is the purpose of the bs16 pin on the 80386 microprocessor?
#: The bus size – 16 input pin allows the interfacing of 16 bit devices with the 32 bit wide 80386 data bus. Successive 16 bit bus cycles may be executed to read a 32 bit data from a peripheral.
What is the function of code prefetch 80386 microprocessor?
2. Code Prefetch Unit. This unit fetches the instructions stored in the memory by making use of system buses. Whenever the system generates a need for instruction then the code prefetch unit fetches that instruction from the memory and stores it in a 16-byte prefetch queue.