This set of Microprocessors MCQs focuses on “80287 Math Coprocessor -2”.
1. If the stack flag is set, and condition code bit C1=1, then the stack is
a) full
b) overflown
c) underflown
d) empty
View Answer
Explanation: If the stack flag is set, and condition code bit C1=1, then the stack has overflown.
2. If the stack flag is set, and condition code bit C1=0, then the stack is
a) full
b) overflown
c) underflown
d) empty
View Answer
Explanation: If the stack flag is set, and condition code bit C1=0, then the stack has underflown.
3. The bits that affect the result of arithmetic operations like ADD, SUB, MUL, DIV are
a) condition code bits
b) rounding control bits
c) masking bits
d) precision control bits
View Answer
Explanation: The precision control bits affect ADD, SUB, MUL, DIV and SQRT results.
4. The precision is decided by the
a) opcode
b) extended precision format
c) opcode or extended precision format
d) none of the mentioned
View Answer
Explanation: For other than the arithmetic instructions (like ADD, SUB, MUL, DIV and SQRT), the precision is decided by opcode or extended precision format.
5. If Numeric Processor Write (NPWR) active-low input pin is activated, then it enables a data transfer from
a) memory to processor
b) 80287 to 80286
c) 80286 to 80287
d) 8086 to 80287
View Answer
Explanation: If Numeric Processor Write (NPWR) active-low input pin is activated, then it enables a data transfer from 80286 to 80287.
6. If Numeric Processor Read (NPRD) active-low input pin is activated, then it enables a data transfer from
a) memory to processor
b) 80287 to 80286
c) 80286 to 80287
d) 8086 to 80287
View Answer
Explanation: If Numeric Processor Read (NPRD) active-low input pin is activated, then it enables a data transfer from 80287 to 80286.
7. Which of the input line(s) indicate that the CPU is performing an escape operation, and enables 80287 to execute the next instruction?
a) NPWR (active low) and NPRD (active low)
b) NPS1 and NPS2 (active low)
c) NPS1 (active low) and NPS2
d) CMD0 and CMD1
View Answer
Explanation: The Numeric Processor select input lines, NPS1 (active low) and NPS2, indicate that the CPU is performing an escape operation, and enables 80287 to execute the next instruction.
8. For which pin of 80286 is the active low pin, BUSY of 80287, connected?
a) ERROR (active low)
b) BUSY (active low)
c) HLDA
d) TEST (active low)
View Answer
Explanation: The BUSY (active low) is connected to the TEST (active low) pin of 80286.
9. If Clock Mode (CM) input pin is held low, then the CLK input is divided by
a) 1
b) 2
c) 3
d) 4
View Answer
Explanation: If Clock Mode (CM) input pin is held high, then the CLK input is directly used for deriving the internal timings. Else, it is divided by 2.
10. Which of the following pin is not involved in the interface of 80287 with 80286?
a) PEREQ
b) ERROR#
c) RESET
d) CMD0 and CMD1
View Answer
Explanation: The 10 pins, PEREQ, PEACK#, BUSY#, ERROR#, NPRD(active low)#, NPWR(active low)#, NPS1(active low)#, NPS2#, CMD0 and CMD1.
11. The PEACK (active low) when activated, the pin that goes into deactivation is
a) PEREQ
b) ERROR#
c) RESET
d) CMD0 and CMD1
View Answer
Explanation: When the data transfer is over, the CPU activates PEACK (active low)# pin, which results in deactivating the PEREQ pin by 80287.
Sanfoundry Global Education & Learning Series – Microprocessors.
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