8:56 AM PT -- TMZ Sports just spoke with boxing legend Roy Jones Jr. -- a long time friend of Pernell -- who tells us how much Whitaker meant to boxing ... and to him personally.
7:26 AM PT -- Pernell took a photo with Floyd Mayweather at an autograph show they were both appearing at in Virginia on the day before he died.
Floyd paid tribute to Pernell on social media saying, "R I P champ, one of the best fighters to ever do it.