CLK_d_normal : d_normal ^2;
CLK_d_normal : 1;
Mvt_Mouse_1 ^2 = CLK_Mvt_Mouse_1,
constraints: [ d_normal ^2 = CLK_d_normal , d_run ^2 = CLK_d_normal, d_stuck ^2 = CLK_d_normal, ...
This basically says that at each instant, all the input events are present. Otherwise, during the simulation, the automatic mode of simulation will most of the time choose the input events to be absent.