1. 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
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. 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
Explanation: The control unit receives, decodes the instructions, and executes the 8087 control instructions.
3. 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
Explanation: The control unit is used for establishing communication between CPU and memory and coordinating the internal coprocessor execution.
4. 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)
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. 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
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. Invalid operation is the exception generated due to
a) stack overflow
b) stack underflow
c) indeterminate form as result
d) all of the mentioned
Explanation: Invalid operation is generated due to stack overflow, stack underflow, indeterminate form as result, or non-number (NAN) as operand.
7.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
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. If the result is infinity, then the exception generated is
a) overflow
b) invalid operation
c) denormalized operand
d) zero divide
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. 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
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. 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
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.