Memory Addressing Techniques

A.

Absolute/Direct - +------+-----+--------------------------------------+ | load | reg |address | +------+-----+--------------------------------------+ (Effective address = address as given in instruction) This requires space in an instruction for quite a large address.

It is often available on CISC machines which have variable-length instructions, such as x86

Some RISC machines have a special Load Upper Literal instruction which places a 16-bit constant in the top half of a register.

An OR literal instruction can be used to insert a 16-bit constant in the lower half of that register, so that a full 32-bit address can then be used via the register-indirect addressing mode, which itself is provided as "base-plus-offset" with an offset of 0

http://en.wikipedia.org/wiki/Addressing_mode(Very

& VINES, Russel.

D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, page 186

also see: http://www.comsci.us/ic/notes/am.html.

The answer to this question is A. direct addressing.

Direct addressing is a type of memory addressing mode where a portion of primary memory is accessed by specifying the actual address of the memory location. In this mode of addressing, the memory location is directly specified in the instruction. The instruction contains the exact address of the memory location where the data is stored or retrieved.

Direct addressing is used in computer programming and is used to access data that is stored in memory. It is a simple and straightforward method of accessing memory because the address of the data is directly specified in the instruction.

Indirect addressing, on the other hand, is a type of memory addressing mode where the memory location is not specified directly in the instruction. Instead, the instruction specifies the address of a memory location that contains the actual address of the data. The processor first reads the address from the specified memory location and then uses that address to access the data.

Implied addressing is a type of addressing mode in which the operand is not explicitly specified in the instruction. The instruction implies the operand based on the opcode or the context of the instruction.

Indexed addressing is a type of memory addressing mode where the address of the data is computed by adding an offset or an index to a base address. This is useful when accessing arrays or other data structures where the data is stored in a sequential manner.

In summary, direct addressing is a type of memory addressing mode where a portion of primary memory is accessed by specifying the actual address of the memory location.