Verification Interview Questions

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You have 2 pieces of rope, each of which burns from one end to the other in 30 minutes (no matter which end is lit). If different pieces touch, the flame will transfer from one to the other. You cannot assume any rope properties that were not stated. Given only 1 match, can you time 45 minutes?
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ASIC Verification Engineer

Interviewed at Zoran

3.7
Sep 9, 2010

You have 2 pieces of rope, each of which burns from one end to the other in 30 minutes (no matter which end is lit). If different pieces touch, the flame will transfer from one to the other. You cannot assume any rope properties that were not stated. Given only 1 match, can you time 45 minutes?

PHONE : 1. Pass by value/ pass by reference. Write a function to swap 2 variables - ll u use pass by value or reference ? 2. Do the same to swap 2 objects (how does it change) 2. Detect 11010 sequence with moore and mealy state machines. 3. Use of const ? What ll happen if you declare above 2 objects as const. 4. Explain NB assignment and blocking assignment. About event regions. 5. Fibonacci -- iterative solution and recursive solution. 6. Disadvantages of a recursive solution. 7. Output of this code fragment : reg a,b,c,d,w; assign w = a; initial begin a = 2; c=5; b<=c; a=5; end what is output of all registers. 8. Explain RISC pipeline. What is the problems. 9. Explain about uvm driver etc. ONSITE : round 1: Round Robin Arbiter Design round 2 : (1) Given a stack class implementation (LIFO) - there are 3 methods - push(), pop(), isempty(). Write a class using objects of given class to implement a FIFO. (2) Make best performance Implement the dist functionality in c++. Given a set of weights mimic to provide randomization skewed to the specification (Basically, write a function that would do something similar to a 'dist' in system verilog). round 3 : Given a divide by 3 state machine. Implement a divide by 5 statemachine. How many vectors are needed to verify it. So the circuit takes serial bit inputs and asserts if the number is a multiple of 3 or 5. round 4 : Circuits project. Basic pipeline architecture. Design a pipeline for a histogram processor. In every cycle we get an instruction (CLR, ADD INCR). Handle dependencies using bypass. round 5 : Given a producer and consumer. They are clocked with the same clock. Producer produces 80 writes for 100 clocks (no random). Consumer reads 8 times per 10 clocks. Find the FIFO depth. Write RTL and verify.
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Verification Engineer

Interviewed at NVIDIA

4.4
Oct 11, 2016

PHONE : 1. Pass by value/ pass by reference. Write a function to swap 2 variables - ll u use pass by value or reference ? 2. Do the same to swap 2 objects (how does it change) 2. Detect 11010 sequence with moore and mealy state machines. 3. Use of const ? What ll happen if you declare above 2 objects as const. 4. Explain NB assignment and blocking assignment. About event regions. 5. Fibonacci -- iterative solution and recursive solution. 6. Disadvantages of a recursive solution. 7. Output of this code fragment : reg a,b,c,d,w; assign w = a; initial begin a = 2; c=5; b<=c; a=5; end what is output of all registers. 8. Explain RISC pipeline. What is the problems. 9. Explain about uvm driver etc. ONSITE : round 1: Round Robin Arbiter Design round 2 : (1) Given a stack class implementation (LIFO) - there are 3 methods - push(), pop(), isempty(). Write a class using objects of given class to implement a FIFO. (2) Make best performance Implement the dist functionality in c++. Given a set of weights mimic to provide randomization skewed to the specification (Basically, write a function that would do something similar to a 'dist' in system verilog). round 3 : Given a divide by 3 state machine. Implement a divide by 5 statemachine. How many vectors are needed to verify it. So the circuit takes serial bit inputs and asserts if the number is a multiple of 3 or 5. round 4 : Circuits project. Basic pipeline architecture. Design a pipeline for a histogram processor. In every cycle we get an instruction (CLR, ADD INCR). Handle dependencies using bypass. round 5 : Given a producer and consumer. They are clocked with the same clock. Producer produces 80 writes for 100 clocks (no random). Consumer reads 8 times per 10 clocks. Find the FIFO depth. Write RTL and verify.

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