US Tourist Visa to Macau?

Hello, I'm living in China with a 365 day tourist visa. I have to leave the mainland every 90 days, so I thought I'd go to Macau because I'm staying in Zhuhai right now. However, I am only allowed to stay in M for 30 days... Does this mean I need to come back to M every 30 days in order to stick to the rules? Or can I stick to the 90 days set by my visa? Thank you for the help, I haven't found any information about this matter online.