Engineering Questions with Answers - Multiple Choice Questions

MCQs on Numeric Processor 8087 -1

1 - Question

The unit that executes all the numeric processor instructions in 8087 is
a) Control unit
b) ALU
c) Numeric extension unit
d) None of the mentioned

View Answer

Answer: c
Explanation: The 8087 is divided into two sections namely control unit and numeric extension unit in which the numeric extension unit executes all the numeric processor instructions.




2 - Question

The unit that receives and decodes the instructions in 8087 is
a) Control unit
b) ALU
c) Numeric extension unit
d) None of the mentioned

View Answer

Answer: a
Explanation: The control unit receives, decodes the instructions, and executes the 8087 control instructions.




3 - Question

The control unit functions in
a) establishing communication between CPU and memory
b) coordinating the internal coprocessor execution
c) reads and writes memory operands
d) all of the mentioned

View Answer

Answer: d
Explanation: The control unit is used for establishing communication between CPU and memory and coordinating the internal coprocessor execution.




4 - Question

When the numeric extension unit (NEU) begins its execution, then the signal that is active is
a) BUSY (active high)
b) BUSY (active low)
c) READY (active low)
d) RESET (active high)

View Answer

Answer: a
Explanation: When NEU begins its execution, the BUSY signal is pulled up. Also, this output signal when high, indicates to the CPU that it is busy with the execution of an allotted instruction.




5 - Question

The register that allows the register programmer to select the required processing options is
a) significant
b) exponent
c) control word register
d) none of the mentioned

View Answer

Answer: c
Explanation: The control word register allows the register programmer to select the required processing options out of available ones. It is used to control the operation of 8087.




6 - Question

Invalid operation is the exception generated due to
a) stack overflow
b) stack underflow
c) indeterminate form as result
d) all of the mentioned

View Answer
Answer: d
Explanation: Invalid operation is generated due to stack overflow, stack underflow, indeterminate form as result, or non-number (NAN) as operand.

 




7 - Question

The exception generated for a too big result to fit in the format is
a) invalid operation
b) overflow
c) denormalized operand
d) result overflow

View Answer

Answer: b
Explanation: A too big result to fit in the format generates this exception. The condition code bits indicate that the result is prohibitively large.




8 - Question

If the result is infinity, then the exception generated is
a) overflow
b) invalid operation
c) denormalized operand
d) zero divide

View Answer

Answer: d
Explanation: If any non-zero finite operand is divided by zero, the zero divide exception is generated. The resulting condition code bits indicate that the result is infinity, even if the exception is masked.




9 - Question

To operate 8087 in maximum mode, the pin MN/MX (active low) is
a) connected to Vcc or power supply
b) connected to ground
c) left unconnected
d) none of the mentioned

View Answer

Answer: b
Explanation: The 8087 can operate in a maximum mode, only when the MN/MX (active low) pin of the CPU is grounded. In maximum mode, all the control signals are derived using a sequence chip known as a bus controller.




10 - Question

If the result is rounded according to the rounding control bits, then the exception generated is
a) denormalized operand
b) underflow
c) inexact result
d) invalid operation

View Answer

Answer: c
Explanation: If it is impossible to fit the actual result in the specified format, the result is rounded according to the rounding control bits, and an exception is generated. This sets the precision exception flag.




11 - Question

The instruction that stores a copy of top of the stack into the memory, and pops the top of the stack is
a) FST
b) FSTP
c) FIST
d) FLD

View Answer

Answer: b
Explanation: FSTP (store floating point number and pop) stores a copy of top of the stack into memory or any coprocessor register, and then pops the top of the stack.




12 - Question

The instruction that multiplies the content of the stack top by 2n is
a) FMUL
b) FPREM
c) FSCAL
d) FCSH

View Answer

Answer: c
Explanation: FSCAL instruction multiplies the content of the stack top by 2n, where n is an integral part of stack and stores the result in stack.




13 - Question

If the opcode bit is D=1, then the source and destination operands are
a) incremented
b) decremented
c) cleared
d) interchanged

View Answer

Answer: d
Explanation: If D=1, then it interchanges the source and destination operands.

Get weekly updates about new MCQs and other posts by joining 18000+ community of active learners