For this loop, you always want to run the same number of iterations, so you dont need the loop count in a variable.
Just put the 8192 directly into A and subtract it.
There is also a handy feature of Hack assembly language that you can have more than one destination on the left of the '='. This lets you easily do "pre increment" assignments.
Your increment and test can become
@i
MD=M+1 // D = ++i
@8192
D=D-A
If you need it elsewhere, you can set a variable to a constant
@8192
D=A
@n
M=D
--Mark