When a microprocessor wants to store a byte of information in memory, or retrieve a byte of information from memory, it needs to refer to the address of the byte in the instruction. When direct addressing is used then the microprocessor instruction refers explicitly to the address that is to be used. When indirect addressing is used then the microprocessor instruction refers to a third object that refers to the address that is to be used. So, for example: Direct addressing: (*) Store the data at address 0x3C6E (*) Deliver the letter to house 12 on the street. Indirect addressing: (*) Store the data at whatever address is in register AX. (*) Deliver the letter to whichever house the occupant of house 7 tells you. So, in indirect addressing, the microprocessor instruction refers to some other "third-party" location (a register or another memory location) to find-out what the ultimate address to be used should be. The instruction does not contain all of the information needed to store the byte (or deliver the letter) but it does say where the missing information can be found. In direct addressing, the instruction contains all of the information needed to store the byte (or deliver the letter). This is basically true for all microprocessors but different microprocessors allow different forms of indirect addressing. For example, some use memory indirect addressing (the third party is another memory location), and some use register indirect addressing (the third party is a register).
Indirect addressing uses a pointer. Indirectly accessing the memory being pointed at is known as dereferencing. Direct addressing uses a variable's name or a reference to obtain the value.
Addressing modes of 8051 are 1.Immediate Addressing Mode 2.Register Addressing Mode 3.Register Indirect Addressing Mode 4.Direct Addressing Mode 5.Implied Addressing Mode and 6.Relative Addressing Mode
The 8086 microprocessor supports several data addressing modes, including immediate, direct, indirect, indexed, and based addressing modes. In immediate addressing, the operand is specified directly in the instruction. Direct addressing involves providing the memory address of the operand. Indirect addressing uses a pointer in a register to reference the operand's memory location, while indexed addressing combines a base address with an offset from an index register. Additionally, based addressing uses a base register to locate the operand in memory.
Double addressing in microprocessors refers to a situation where two different addresses are used to access the same memory location or resource. This can occur in scenarios involving multiple data buses or when both direct and indirect addressing modes are employed. It can lead to increased complexity in memory management and may result in ambiguous data retrieval if not handled carefully. Proper management of addressing schemes is crucial to ensure data integrity and optimal performance in microprocessor operations.
In the 8086 microprocessor, register indirect addressing mode is a method of accessing data in memory using a register to hold the address of the data. In this mode, the effective address of the operand is provided by a register, such as BX, SI, or DI. This allows for flexible data manipulation, as the contents of the register can be easily modified to point to different memory locations. This addressing mode is particularly useful for operations on arrays and data structures.
literal and absolute direct are the registers
Feces and smells.
Do you mean what is the difference between a microprocessor and microcode? Microcode is an instruction sequencer found in CISC architectures. It's job is to take the machine code and break it down into a sequence (usually steps of 4) to execute things such as indirect register references and other multi-step instructions.
The I bit is 0 so the instruction is recognice as a direct address instruction The indirect address instruction needs 2 referance to memory to fetch & opened The I bit is 1 so the instruction is recognice as a indirect address instructionhe
There are 256 ports available in the 8085 microprocessor. The IN and OUT instructions have an 8-bit port number, and that is where the 256 comes from.In order to use ports, the hardware addressing system must decode IO/M-. Some implementations don't do this, so they map IO addresses to memory addresses. In that case, you could say there are 65536 possible IO addresses, but that is not the same as ports, because ports are specific to the IN and OUT instructions.The other "problem" with IN and OUT is that you cannot specify the address in a register, while you can do so with indirect memory addressing.
there are five addressing modes in 8086 they are : 1->direct addressing 2->Indirect addressing 3->index addressing 4->immediate addressing 5->register addressing
DI is the Index register in Data segment(16-bit, 64 KB) .Destination Index (DI) is a 16-bit register. DI is used for indexed, based indexed and register indirect addressing, as well as a destination data address in string manipulation instructions.