Floyd Mayweather's days of trashing his dad are LONG OVER -- in fact, TBE tells TMZ Sports why he owes his entire boxing empire to his pops! 

Of course, Floyd Jr. and Floyd Sr. have a very famous, very nasty feud that left them estranged for years. At one point, Sr. offered to train fighters to BEAT his own son. 

Oh, and don't forget that other time Sr. said he used Floyd as a human shield to keep Jr.'s maternal uncle from shooting him with a shotgun!!! Seriously!!

But all that's water under the bridge ... Floyd Jr. says he owes "all the thanks to my dad."

He also says Sr. gave him the single most important piece of advice he ever got about his career ... and he never forgot it. 

Floyd also wants everyone to remember he ain't no bitch -- and used to be known as a "knockout artist" before his body broke down. 

He ain't lyin ...