86 THE x86 MICROPROCESSORS
An assembly language line has four fi elds, namely, label, opcode, operand and comment. A label
is positioned at the left of a line and is the symbol for the memory address which stores that line
of information. ere are certain rules regarding labels that are allowed under MASM.
All labels should begin with a letter or the special characters @, i) $, _ and ?
A label can have 1 to 31 characters which may be digits, letters in upper or lower case or the ii)
special characters at (@), dollar ($), underscore (_), dot (.) or question mark (?).
No reserved words of MASM may be used.iii)
Each label must be unique.iv)
e second fi eld is the opcode or instruction fi eld. e third is the operand fi eld, and the last is ...