I am a student of Electrical Engineering and my area of specialisation being Power Systems, I have no idea of DSP and Embedded Systems.
That is sooo sad. If you had attended class (and done your homework) that would not have been so.

My professor wants the work in a day and say even if i manage to write the code i will not able to compile them and convert them to 8051 compatible hex format coz the softwares i have do not support more than 4kb of code.
I am sure (s)he did not ask for it just now - If (s)he did, (s)he is asking the impossible, complain and refuse.

Can somebody plzz provide me with the so required code in C and in 8051 compatible hex by tonight.
I hope not since that would be cheating.

if I have to avoid an extension (which would mean my losing my job)
For the sake of your employer I hope nobody will help you, since the employer will be severely disappointed with someone that has passed a course without doing the work.

so that i can get my work done
So you can get your work done. Something does not jive here, if you are to do your work, then, how come, you are asking for someone else to do it.

i'll try to pay u as much as i can afford to from my first salary
With you, obviously, not having put any effort into the class I would not bet on you ever collecting a salary.

Erik