help with atmega168 assembly adc code

[smm4k]

hi assembly professionals, i am doing a robot project and i intent to use assembly language to control the brain of the robot which is an atmega168 microcontroller. I have programmed the adc successfully the controller using arduino C language but i have a problem using studio4 assembly.
here is the code i tried to write using the data sheet in assembly which gives me errors,

ad_init:
ldi rmp, 0b00000000
out ADMUX, rmp
ldi rmp, 0b11001111
out ADCSRA, rmp
ad:
in tmp, ADCSRA
ldi rmp, 1<<ADSC
or tmp, rmp
out ADCSRA, tmp
ad_loop:
in rmp, ADCSRA
andi rmp, 1<<ADIF
ldi tmp, 1<<ADIF
cpse rmp, tmp
breq ad_loop
ad_done:
ret

so if any one has been successful in programming the same in assembly is welcome to help, please.