8086 processor 8085 Vs 8086 8085 8 bit

8086 processor

8085 Vs 8086 8085 8 -bit processor created in 1977 Consists of 6200 transistors 16 bit address line which can access 64 KB memory location No. of flags are 5 16 bit processor developed in 1978 29000 transistors approx. 20 bit address bus which can access 1 MB memory location No. of flags are 9 8086 uses pipelining 6 byte queue in BIU available Pipelining Concepts is not used Instruction Q does not exist only sequential execution available 8086 Only 5 types of addressing modes 8 types of addressing modes available

Architecture of 8086

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Pipelining Fetching the next instruction while the current instruction is under execution is called pipelining. • Load • Execute • Store Load: read instruction from memory Execute: execute instruction Store: store instruction memory/register •

Traditional Pipeline Concept Laundry Example Ann, Brian, Cathy, Dave each have one load of clothes A to wash, dry, and fold Washer takes 30 minutes Dryer takes 40 minutes “Folder” takes 20 minutes B C D

Traditional Pipeline Concept 6 PM 7 8 9 10 Midnight 11 Time 30 40 20 30 A B C D 40 20 Sequential laundry takes 6 hours for 4 loads If they learned pipelining, how long would laundry take?

Traditional Pipeline Concept 6 PM T a s k O r d e r 7 8 9 10 11 Midnight Time 30 A B C D 40 40 20 � Pipelined laundry takes 3. 5 hours for 4 loads

Use the Idea of Pipelining in a Computer Fetch + Execution Time I 1 I 2 I 3 Time Clock cycle F 1 E 1 F 2 E 2 F 3 E 3 I 2 Interstage buffer B 1 Instruction fetch unit I 3 Execution unit (b) Hardware organization 2 F 1 E 1 3 4 Instruction I 1 (a) Sequential execution 1 F 2 E 2 F 3 E 3 (c) Pipelined execution Figure. Basic idea of instruction pipelining.

Use the Idea of Pipelining in a Computer Fetch + Decode + Execution + Write

Flag register

Pin diagram of 8086