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Explore the evolution of CPUs from Intel 8080 to modern processors, analyzing efficiency metrics, instruction sets, memory addressing, and programming styles. Learn about pipelining and key capabilities. Takeaway the complexity and power of CPU development.
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ITEC 352 Lecture 23 CPU analysis
Review • Pipelining • Long • Short • Bubbles • Branches • Efficiency
Outline • CPU • History • Evolution
Intel 8080 • 40 pins • How does this compare w/ your breadboard? • 7 registers • 78 instructions • 65,536 bytes of addressable memory • Programmable stacks As described in the manual
Registers • A-H or 0-7 • A was the accumulator (where results were stored) • Pairs • Some instructions required certain registers to be used • I.e. B and C would be used for a certain instruction • Has a PSW (1 byte) in register A that stores the state of the machine
Memory • 64k possible memory (2^16) • 8 bit cpu (no direct way to handle 16 bits) • Stack pointer • Programmer maintained • Instruction augmented • Program counter • 16 bits to tell CPU where to get next instruction • Instructions could be 1,2, or 3 bytes • Cautions against storing data and instructions together
Addressing • Direct • Uses a register • Immediate • Instruction then address in memory • Stack • Convention for first / second places to get memory (pairs)
Assembly • Style • Label Code Operand ;Comment • Data • Hex, Binary, Octal • Instructions • +,-,*,mod,and,or,not,shr,shl,xor • mvi register address • jmp address All arithmetic operations assume 2s complement format
Assembly(2) • DW,DB,DS • Define a place in memory • MOV, LDAX, STAX (Load/Store register A) • CMP = Compare register / memory w/ register A • DAD • The double add (16 bit on an 8 bit) • Many others, but same complexity level
Stack • push registerPair • pop registerPair • inx register (increment pointer) Put / Store registers / memory
Capabilities? • What can a 2 Mhz CPU do? Not an intel CPU. However 1.76Mhz and ~15 MMapped registers
Pentium 3 P3
Takeaway • CPU development is amazing • Double edged sword • When and why to goto low level
Summary • CPU