In reply to Ajeetha Kumari CVC:
We strongly discourage changing this the size of this as it impacts all ovm_int_fields.
Even stronger recommendation is not to use any of the field macros - they are terrible for performance. See http://verificationhorizons.verificationacademy.com/volume-7_issue-2/articles/stream/are-ovm-and-uvm-macros-evil-a-cost-benefit-analysis_vh-v7-i2.pdf