Simpletron

Question 1

fetches instructions,
decodes instructions, causes
instructions to be carried out

Answer 1

Control Unit

Question 2

a special register with
individual bit positions that give
the status of the CPU (control
flags) or results of arithmetic
operations (status flags)

Answer 2

Flags

Question 3

always
contains the offset of the next
instruction. The IP and CS
registers combine to form the
complete address. IP is also
known as PC – the program
counter.

Answer 3

IP(Instruction Pointer)

Question 4

Branches to a specific location in
memory

Answer 4

BRANCH 40

Question 5

Branches to a specific location in
memory if the accumulator is
negative

Answer 5

BRANCHNEG 41

Question 6

Branches to a specific location in
memory if the accumulator is zero

Answer 6

BRANCHZERO 42

Question 7

HALT

Answer 7

43

Question 8

Reads a word from the terminal into
a specific location in memory

Answer 8

READ 10

Question 9

Writes a word from a specific
location in memory to the terminal

Answer 9

WRITE 11

Question 10

Loads a word from a specific
location in memory into the
accumulator

Answer 10

LOAD 20

Question 11

Stores a word from the accumulator
into a specific location in memory

Answer 11

STORE 21

Question 12

Adds a word from a specific location
in memory to the word in the
accumulator(Leaves the result in the accumulator)

Answer 12

ADD 30

Question 13

Subtracts a word from a specific
location in memory from the word in
the accumulator
(leaves result in the accumulator

Answer 13

SUBTRACT 31

Question 14

fetches instructions,
decodes instructions, causes
instructions to be carried out

Answer 14

Control Unit

Question 15

performs arithmetic operations
(addition, etc.) on data.

Answer 15

Arithmetic logical unit (ALU)

Question 16

high speed memory cells
(don’t need to go through the bus to
access). They vary in number and
purpose on different machines.

Answer 16

Registers

Question 17

communication pathways
connecting different
devices/components

Answer 17

Buses

Question 18

also known as
general purpose registers: AX,
BX, CX, DX

Answer 18

Data registers

Question 19

Used for arithmetic operations
and data movement

Answer 19

Data registers

Question 20

fastest for
arithmetic operations. Some math
instructions only use AX.

Answer 20

AX – accumulator

Question 21

This register can hold an
address of a procedure or variable.
BX can also perform arithmetic and
data movement.

Answer 21

BX – base

Question 22

this register acts as a
counter for repeating or looping
instructions

Answer 22

CX – counter

Question 23

this register has a
special role in multiply and divide
operations. In multiplication it holds
the high 16 bits of the product. In
division it holds the remainder.

Answer 23

DX – data

Question 24

are used as
base locations for program
instructions, data, and the stack.

Answer 24

Segment registers

Question 25

All references to memory involve a segment register as the base location

Answer 25

Segment registers

Question 26

this register holds the base location of all instructions in a program

Answer 26

CS – code segment

Question 27

this is the default base location for variables. It is used by the CPU to calculate the variable location.

Answer 27

DS – data segment

Question 28

this register contains the base location of the stack.

Answer 28

SS – stack segment

Question 29

this is an additional base location for memory variables

Answer 29

ES – extra segment

Question 30

contain the offsets of data and instructions.

Answer 30

Index registers

Question 31

Offset refers to the distance of a variable, label, or instruction from its base segment.

Answer 31

Index registers

Question 32

are used when processing strings, arrays, and other data structures.

Answer 32

Index registers

Question 33

this register contains an offset from the SS register and is often used by subroutines to find the variables passed to it on the stack.

Answer 33

BP – base pointer

Question 34

this register contains the offset from the top of the stack. The complete top of stack address is calculated using the SP and SS registers.

Answer 34

SP – stack pointer

Question 35

used to point to data in memory. Named because this is the index register commonly used as the source in string operations (for example)

Answer 35

SI – source index

Question 36

index register commonly used as the destination in string operations

Answer 36

DI - destination index

Question 37

set if the result of an unsigned operation is too big to fit into the destination. 1 = carry, 0 = no carry

Answer 37

Carry flag (CF)

Question 38

set if the result of a signed operation is too wide to fit into the destination. 1 = overflow, 0 = no overflow.

Answer 38

Overflow flag (OF)

Question 39

set when the result of an operation is negative. 1 = negative, 0 = positive

Answer 39

Sign flag (SF)

Question 40

set when the result of an arithmetic operation is zero. Used by branch and loop instructions when comparing values. 1 = zero, 0 = not zero.

Answer 40

Zero flag (ZF)

Question 41

set when an operation causes a carry from bit 3 to bit 4 or a borrow from bit 4 to bit 3. 1= carry, 0 = no carry

Answer 41

Auxiliary Carry

Question 42

indicates if the result of an operation has an even or odd number of bits. Used to verify memory integrity or correct transmission of data.

Answer 42

Parity

Question 43

a number referring to an 8- bit memory location

Answer 43

Address

Question 44

the Simpletron uses a keyboard for input and a terminal screen for output

Answer 44

I/O

Question 45

the form or structure of the expressions, statements, and program units

Answer 45

Syntax

Question 46

the meaning of the expressions, statements, and program units

Answer 46

Semantics

Question 47

is a string of characters over some alphabet

Answer 47

sentence

Question 48

is a set of sentences

Answer 48

language

Question 49

is the lowest level syntactic unit of a language

Answer 49

lexeme

Question 50

is a category of lexemes (e.g., identifier)

Answer 50

token

Question 51

A recognition device reads input strings over the alphabet of the language and decides whether the input strings belong to the language

Answer 51

Recognizers

Question 52

A device that generates sentences of a language

Answer 52

Generators

Question 53

One can determine if the syntax of a particular sentence is syntactically correct by comparing it to the structure of the generator 4

Answer 53

Generators

Question 54

Developed by Noam Chomsky in the mid‐1950s

Answer 54

Context‐Free Grammars

Question 55

Invented by John Backus to describe Algol 58

Answer 55

Backus‐Naur Form (1959)

Question 56

is one in which the leftmost nonterminal in each sentential form is the one that is expanded

Answer 56

leftmost derivation

Question 57

may be neither leftmost nor rightmost

Answer 57

derivation

Question 58

is ambiguous if and only if it generates a sentential form that has two or more distinct parse trees

Answer 58

grammar

Question 59

Designed in 1945, but not published until 1972 * Never implemented * Advanced data structures * floating point, arrays, records * Invariants

Answer 59

Zuse’s Plankalkül

Question 60

Distributed in 1958 * Independent compilation * Fixed the bugs

Answer 60

Fortran II

Question 61

The ease with which programs can be moved from one implementation to another

Answer 61

Portability

Question 62

The applicability to a wide range of applications

Answer 62

Generality

Question 63

The completeness and precision of the language's official definition

Answer 63

Well-definedness

Question 64

Programs are translated into machine language

Answer 64

Compilation

Question 65

Programs are interpreted by another program known as an interpreter

Answer 65

Pure interpretation

Question 66

A compromise between compilers and pure interpreters

Answer 66

Hybrid implementation systems

Question 67

Languages are developed around prevalent computer architecture known as the von Neumann architecture

Answer 67

Computer architecture

Question 68

The user and system code together

Answer 68

Load module

Question 69

The process of collecting program units and linking them to a user programs

Answer 69

Linking and loading

Question 70

Are commonly used to specify that code from another file is to be included

Answer 70

Preprocessor macros

Question 71

Developed at MIT in mid 1970s * Small * Extensive use of static scoping * Functions as first‐class entities * Simple syntax (and small size) make it ideal for educational applications

Answer 71

Scheme

Question 72

Evolved during 1960‐62 * Explicit type declarations * Logical selection statement * Subprogram names could be parameters * ANSI standard in 1966

Answer 72

Fortran IV

Question 73

Became the new standard in 1978 * Character string handling * Logical loop control statement IF-THEN-ELSE statemen

Answer 73

Fortran 77

Question 74

most significant changes from Fortran 77 * Modules * Dynamic arrays * Pointers * Recursion * CASE statement * Parameter type checking

Answer 74

Fortran 90

Question 75

latest versions of Fortran

Answer 75

Fortran 95, fortran 2003

Question 76

An effort to combine features of several dialects of LISP into a single language * Large, complex

Answer 76

COMMON LISP