Check out the CJNE instruction. The instruction is CJNE operand1,operand2,BranchAddress

"The Carry bit (C) is set if operand1 is less than operand2, otherwise it is cleared."

So a common structure is:

CJNE A,address,$+3
JC A_smaller_than_address
SJMP A_greater_or_equal_to_address

Additionally, CJNE doesn't change accumulator nor the contents of address while SUBB will change the accumulator.

Good luck,
Craig Steiner