I typed the following simple code in the Ride 7 and ran it.

org 0h
mov 89h,#01h
here: mov 8ch,#00h
mov 8Ah,#00h
setb 8ch
again: mov 080h,8ch
mov 090h,8Ah
jnb 8dh,again
clr 8ch
clr 8dh
end

BUT the timer registers th0 and tl0 do not increment at all after setting tr0(address 8ch) high. I executed the same code on another simulator edsim 51 and it worked well.
I am not able to find the problem.
the code has no syntax errors and project builds successfully.
help anyone??