Use the EQU directive.
.386 .model flat,stdcall .stack 4096 ExitProcess PROTO, dwExitCode:DWORD .data ;EQU directive defines a symbol by either an integer or text ;EQU directive makes the symbolic constant so it can't be redefined. str1 EQU <"apple",0> str2 EQU <"orange",0> str3 EQU <"grape",0> str4 EQU <"melon",0> var1 BYTE str1 var2 BYTE str2 var3 BYTE str3 var4 BYTE str4 result DWORD 1234567h .code main PROC mov eax,0 ;clarity purposes mov ebx,0 mov edx,0 mov ecx,0 mov al, var1 ; al = 61h which is 'a' in ascii mov bl, var2+1 ; bl = 71h which is 'r' in ascii mov cl, var3+2 ; cl = 61h which is 'a' in ascii mov dl, var4+3 ; dl = 6Fh which is 'o' in ascii INVOKE ExitProcess,0 main ENDP END main