In the first case u can access the memory from 00h to FFh with value in dptr as the offset.
In the second case u can access memory from 0000h to FFFFh with value in acc as the offset.
The memory offset just now i mentioned also depends on the initial values that acc and dptr hold before entering these routines, bcz ur not assigning any values to acc or to dptr in the start of these two modules.

hope i am clear
-sathish