Floyd Mayweather's Dad -- 50 CENT SHOULD FIGHT MY SON ... That Would End the Feud

Floyd Mayweather Sr. is sick and tired of 50 Cent cracking jokes at his son's expense -- and says the real laughs would come if the two ever fought ... because Floyd would kick 50's WHOLE ASS!

Daddy Mayweather made the comments during an interview with Brian Shapiro from "The Vegas Take" on Fox Sports 670 Las Vegas -- and explained why he thinks 50 has declared war on Floyd.

"50 Cent seems like he's got a problem since Floyd left him. He's a world known singer and he's acting like a kid."

Money Sr. says the real hilarity would ensue if Floyd and 50 ever got in the ring ... promising that the 147 lb. Mayweather would punish the two-hundred-and-something pound rap star.

"He weighs over 100 pounds more than Floyd. Let him go up against Floyd ... put that on video. Floyd would stop all that. Wouldn't be no more said."

There were rumors that Floyd recently challenged 50 to a 12 round fight -- but that later turned out to be a hoax.