The Evolution of the Intel 80x86 Architecture Chad Derrenbacker Chris Garvey Manpreet Hundal Tom Opfer CS 350 December 9, 1998

Development Time line 1978 Intel 8086: 16 bit registers, 1MB memory 8088 was released, 8 bit external registers 1982 Intel 80286: 16 bit registers, two addressing modes, 16MB memory 1985 Intel 80386: 32 bit registers, three addressing modes, 4 Gig memory 1989 Intel 80486: 32 bit registers, three addressing modes, 4 Gig memory, faster Mhz speed, FPU, L1 cache Intel Pentium

Instruction Set Data movement instructions –PUSH (push word onto stack), MOV (move byte or word) Conversions –CBW (convert byte to word), CDQ (convert double to quad) Arithmetic instructions –ADC (add with Carry), INC (Increment) Logical, shift, and rotate instructions –XOR (Exclusive OR), ROL (Rotate Left) String instructions –STOS (store string), LODS (load string) Program flow and control –CALL (program call), JMP (unconditional jump)

Register Architecture Register sizes progressed from 16 bit on the 8086 and 286 to 32 bit on the 386 and 486. General Registers –Accumulator, Base, Counter, Data Segmented Registers –Code, Data, Stack, Extra Special Purpose Registers –Stack, Base, Stack, Destination –Instruction, Flag

Addressing Modes 8086 –only operated in Real Mode –Introduced Protected mode: allowed memory to be segmented and protected from conflicts. –Problem was that it couldn’t switch back to Real 80386, 486 –Virtual Mode: allowed chip to emulate multiple 8086 chips –able to address memory in large chunks

Performance Factors Few improvement from –introduction of cache memory –integration of 386 match coprocessor into 486 core logic –introduction of 486DX2 and DX4 (doubled and tripled core clock frequency)

Memory 8086 –memory segmentation (total address space 1MB, 64K at a time) –16MB Physical memory, 1GB Virtual memory –4GB Physical memory, 64TB Virtual memory –same as 80386

Speed 8086 –4.77 (0.33 MIPS), 8 (0.66 MIPS), 10 (0.75 MIPS) MHz –6 (0.9 MIPS), 10 (1.5 MIPS), 12 (2.66 MIPS) MHz –DX 16, 20, 25 (8.5 MIPS), 33 MHz –SX 16, 20 (2.5 MIPS), 33 (2.9 MIPS) MHz –DX 25 (20 MIPS), 33, 50 (41 MIPS) MHz –DX2 66 (54 MIPS) MHz –DX4 100 MHz - clock tripling –able to execute most instructions in a single cycle with the incorporation of RISC like principles.

Role in the Marketplace 6 generations, most successful microprocessor in history Intel was in the right place at the right time when IBM made their decision to use the 8086 in the first desktop computer, the Datamaster IBM’s own engineers wanted to use the Motorola 68000, but they already had the rights to manufacture the PC AT, a 6 MHz computer using PC-DOS, a 5.25-inch 1.2MB floppy drive, with 256KB RAM for $4000.

Role in the Marketplace Cloning of the IBM-PC –1986 Compaq introduced the first MHz clone. –Turning point that enabled today’s modern computer industry. Today the x86 market is a multi-billion dollar industry selling millions of units per year. Intel’s Key Factors in Success: –Double the speed of the latest microprocessor every 18 months –expand into other markets such as notebooks –keep new processors upwardly compatible

Questions?