Need of assume

Hi members,
what happens when 'assume' directive is used and not used in assembly language of 8086? I googled it but couldnt find perfect answer. Please help. Thanks in advance

You mean like "ASSUME cs:CodeSegment ss:StackStart" - that kind of thing?

This is used with segmented memory when you are in Real Mode - say returning from an interrupt in Protected Mode. "CodeSegment" and "StackStart" would be names you defined those segments with - ASSUME tells the compiler these are the segments to start using, so it doesn't accidentally reference a register at the same location in the previously used segments.

Thanks duffy