1,000+ ASIC Interview Questions: SystemVerilog, UVM & RTL

DescriptionQ351

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Q351DVMetaASIC interview problem

Random palindrome array constraint

TechniquesDVSystemVerilogDynamic arrayReduction

DifficultyMedium

TopicSystemVerilog Constraints

LanguageSystemVerilog

Requirements4 checkpoints

Problem

A sequence item needs a short digit array that reads the same forward and backward. Write constraints for size, digit range, full palindrome symmetry, and a bounded sum.

Class declarationSystemVerilog

class palindrome_item;
  rand int unsigned digits[];
endclass

Example input and output

Use this case to check your interpretation

Input

digits='{4,0,1,1,0,4}

Output

Legal; size=6 and sum=10

Explanation

Every element equals its mirror, every digit is 0..9, and the total is within 36.

Requirements (4)

Constrain digits.size() to be from 5 through 9 inclusive.
Constrain every element to the inclusive range 0 through 9.
For every valid index i, constrain digits[i] to equal digits[digits.size()-1-i].
Constrain the sum of all digits to be no greater than 36.