difference between sensitivity list and wait vhdl
The two processes as you have written them are almost equivalent. If you move the wait statement to the end of the second process, then they are exactly equivalent. The difference is whether or not the body of the process gets executed before the first change on any of the listed signals.



IEEE Std 1076-2008 11.3 para 4 (in part):


  If a process sensitivity list appears following the reserved word process, then the process statement is assumed to contain an implicit wait statement as the last statement of the process statement part; this implicit wait statement is of the form wait on sensitivity_list ; where the sensitivity list is determined in one of two ways. If the process sensitivity list is specified as a sensitivity list, then the sensitivity list of the wait statement is that following the reserved word process. ...