CECS 341 – Computer Design Primer.1(c) R. W. Allison

CECS 341 – Computer Design Primer.2(c) R. W. Allison 1: the art or science of building; specifically : the art or practice of designing and building structures… What is architecture? (Merriam-Webster.com) Perspectives (Latin: from per- through + specere to look; hence, to see through, clearly) 1: Instruction Set Architecture (ISA)1: Instruction Set Architecture (ISA) 5: the manner in which the components of a computer or computer system are organized and integrated Fully defined in Programmers Reference ManualsFully defined in Programmers Reference Manuals a.k.a. “exo-architecture”a.k.a. “exo-architecture” 2: Micro-Architecture2: Micro-Architecture Defined in Data and Control Paths using “RTL” and micro-instructionsDefined in Data and Control Paths using “RTL” and micro-instructions a.k.a. “endo-architecture”a.k.a. “endo-architecture”

CECS 341 – Computer Design Primer.3(c) R. W. Allison What do computers do?What do computers do? Computers execute Instructions!Computers execute Instructions! How do they execute instructions?How do they execute instructions? With a Finite State Machine (FSM)!With a Finite State Machine (FSM)! 2) Decode – determine (a) operation and (b) operands2) Decode – determine (a) operation and (b) operands 3) Execute – execute the operation and return results3) Execute – execute the operation and return results Fetch 1) Fetch – read the instruction from memory1) Fetch – read the instruction from memory Decode Execute What kind of “instructions” do they execute?What kind of “instructions” do they execute? Aha, here’s the “rub.”Aha, here’s the “rub.” Do an upper-campus survey (All the answers would be correct)

CECS 341 – Computer Design Primer.4(c) R. W. Allison if (Y>X) then A=B+C;H.L.L. (high-level language) (Processor independent) else A=B–C; (Processor independent) (compiler) (assembler) (CPU designer—i.e. you) ( μ- assembler—e.g. you) R7  R2 + R5RTL (register transfer language) machine language (machine code) (the instructions that are actually executed) 111_010_101_0010_ Control Words (μ-instructions) (a.k.a. μ-code) add R7, R2, R5Assembly language (e.g. x86, ARM) Weeks 1 to 5 (H&P Ch. 2) Weeks 6 to 10 (H&P Ch. 4) (exo)(endo)

CECS 341 – Computer Design Primer.5(c) R. W. Allison  Numbering and Coding Systems l Decimal and binary number systems l Converting from decimal to binary l Converting from binary to decimal l Hexadecimal system  Conversion to/from binary  Conversion to/from decimal  Adding/subtracting binary and hex numbers  Two’s complement representation  Powers of 2 “versus” Powers of 10 l 2 8 = 256 l 2 10 = 1Kilo (1024) 10 3 = 1,000 l 2 20 = 1Mega ( = 1,048,576 ) 10 6 = 1,000,000 l 2 30 = 1Giga ( = 1,073,741,824) 10 9 = 1,000,000,000 l 2 40 = 1Tera ( = 1,099,511,627,776) = 1,000,000,000,000

CECS 341 – Computer Design Primer.6(c) R. W. Allison  The basic data types used by processors, expressed as binary values, are signed and unsigned integers that are “n-bits” wide (e.g. 8-bit, 16-bit, 32-bit, 64-bit).  Range of “n-bit” unsigned integer (all are positive) 0 (min) to 2 n – 1 (max) l Examples:8-bit unsigned 0 to 2 8 – 1  0 to bit unsigned 0 to 2 16 – 1  0 to 65,535  Range of “n-bit” signed integer (half are negative, half are positive) -2 n-1 (min) to 2 n-1 – 1 (max) l Examples:8-bit signed -2 7 to 2 7 – 1  -128 to bit signed to 2 15 – 1  to  Signed integers are represented in two’s complement format