1. a symbolic address consist not more than 3 alphanumeric characters.

2.First characters must be a letter

3.a symbolic address in label field is terminated by  a comma so that itll be recognized as label by assembler

4. instruction field can specify memory refrence instruction or non memory reffrence instruction or psuedo instruction with or without operand

5. a memory refrence instruction occupies two or three symbol separated by spaces. the first 3 letter must be defining an mri operation

assembly language program to find 2's complement of a number:

		ORG 505	/origin of program is location 505
		LDA A	/load decimal number A to AC
		CMA	/complement AC
		INC	/increment AC
		STA A	/store 2's complement of A
		HLT	/halt computer
A,		DEC N	/signed decimal number N (decimal operand)
		END	/end of symbolic program