What is the explanation for the memory organization of 8086?

Answer 1

Two types of memory organization are used:

Linear addressing where the entire memory is available to the processor at all the times ( Motorola 68000 family).

Segmented addressing where the memory space is divided into several segments and the processor is limited to access program instructions and data in specific segments.

Answer 2

Except for the

instruction register, which is actually a 6-byte queue, the control unit

and working registers are divided into three groups according to their

functions. There is a data group, which is essentially the set of

arithmetic registers; the pointer group, which includes base and index

registers, but also contains the program counter and stack pointer; and

the segment group, which is a set of special purpose base registers. All

of the registers are 16 bits wide.

The data group consists of the AX, BX, CX and DX registers. These

registers can be used to store both operands and results and each of

them can be accessed as a whole, or the upper and lower bytes can be

accessed separately. For example, either the 2 bytes in BX can be used

together, or the upper byte BH or the lower byte BL can be used by

itself by specifying BH or BL, respectively.