5_25278_37.pdf - Segment Offset Memory address Since all...

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Segment: Offset Memory addressSince all registers in the 8086 are 16 bits wide, the address space is limited to 216, or 65,536 (64 K) locations.¾the memory is organized as a set of segments¾Each segment of memory is a linear contiguous sequence of up to 64K bytesIn this segmented memory organization, we have to specify two components to identify a memory location: a segment base and an offset
¾This two-component specification is referred to as the logical address.The segment base specifies the start address of a segment in memory (called paragraphs)that can exist in a 20-bit address space The offset specifies the address relative to the segment base. The offset is also referred to as the effective address.¾The Instruction Pointer register contains the offset address of the next sequential instruction to be executed
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Once the paragraph boundary is established by the segment register, the offset value (either a literal or register content) is sign extended and added to the shifted value from the segment register to form the full 20-bit address

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