Microprocessors and Microcomputer-Based System Design, 2nd Edition

4.2.1.a Memory Organization and Segmentation

The 4-gigabyte physical memory of the 80386 is structured as 8-bit bytes. Each byte can be uniquely accessed by a 32-bit address.

The programmer can write assembly language programs without a knowledge of physical address space.

The memory organization model available to applications programmers is determined by the system software designers. The memory organization model available to the programmer for each task can vary between the following possibilities:

• •  A “flat” address space includes a single array of up to 4 gigabytes. Even though the physical address space can be up to 4 gigabytes, in reality it is much smaller. The 80386 maps the 4-gigabyte flat space into the physical address space automatically ...