Arguments are passed to subs as a list. if you have foo($arg1,@moargs) it will recieve @_ = ($arg1,@moargs). In list context list elements are placed in the list in order. However prototypes can change the way the arguments are evaluated. foo (\@\%) causes perl to treat foo(@argar,%arghs) as foo(\@argar,\%arghs).

This is all explained in perlsub which draws on information in perlfunc and perlop.