COA_Ch04_InClass-2

The ___________ of a machine specifies the instructions that the computer can perform and the format for each instruction.

• control unit
• CPU
• instruction set architecture
• fetch-decode-execute cycle

The _____ register keeps track of the next instruction to be fetched.

• program counter
• accumulator
• address register
• memory buffer register

The register that holds the actual data to be read from or written to a given memory address is called:

• memory address register
• index register
• memory buffer register
• none of these

Which MARIE instruction is being carried out by the RTN statement that follows? PC ← X

• Store X
• JnS X
• Load X
• Jump X

Among other things, assembler directives can:

• determine the next action after numeric overflow
• distinguish a value as hexadecimal or decimal
• invoke interrupt service routines
• control conditional assembly using macro instructions

One good reason to use assembly language is to compensate for shortcomings in optimizing compilers for higher-level languages. Interrupt checking is typically carried out at various times during the execution of a machine instruction.

• True
• False

During the second pass of an assembler:

• instructions are only partially assembled
• the symbol table is only partially completed
• addresses from the symbol table are placed in object code
• external code is merged with the object code

If a system's entire set of microoperations consists of 92 statements, how many bits must be used for its microop code?

• 7
• 8
• 64
• 92