OVERVIEW OF THE 80C186 FAMILY ARCHITECTURE

2.1.7Memory Segmentation

Programs for the 80C186 Modular Core family view the 1 Mbyte memory space as a group of user-defined segments. A segment is a logical unit of memory that can be up to 64 Kbytes long. Each segment is composed of contiguous memory locations. Segments are independent and sep- arately addressable. Software assigns every segment a base address (starting location) in memory space. All segments begin on 16-byte memory boundaries. There are no other restrictions on seg- ment locations. Segments can be adjacent, disjoint, partially overlapped or fully overlapped (see Figure 2-6). A physical memory location can be mapped into (covered by) one or more logical segments.

2-8

Page 37
Image 37
Intel 80C186XL, 80C188XL user manual Memory Segmentation