In what order does TGM calculate tetromino movement? DAS -> gravity -> soft drop or some other order? I am asking because for example if gravity was calculated before DAS, then a piece could be in a "floating" state in 20G.
Rotation, then DAS, then gravity. This enables moves like the one shown in the fourth section of this page.
The processing order. If a piece is spawning. 1) initial hold 2) initial rotate without wallkick 3) initial drop. then after this, and every frame. 4) rotation 5) movement 6) gravity. In 20g, a piece is never in midair at any time.