[Advaita-l] veda saMhita - pada vibhAga

[Bhaskar YR]

praNAms
Hare Krishna

My doubt is :  who did the pada vibhAga of veda saMhita portion?? Is it done by vEdavyAsa who did the segregation of veda-s??   any stipulated rules (grammar rules) for doing pada ccheda which is the basis for chanting the saMhita mantra-s in krama, jata, ghana pATa pattern??  Any pointers will be highly appreciated.

Hari Hari Hari Bol!!!
bhaskar