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Random palindrome array constraint

MediumSystemVerilog ConstraintsSystemVerilog

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.

Starting point

Question code

class palindrome_item;
  rand int unsigned digits[];
endclass
Reviewed example

Work through one case

Input
digits='{4,0,1,1,0,4}
Expected output
Legal; size=6 and sum=10

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

What to cover

Requirements

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