MASM Sum of Ascii in a string

Question

INCLUDE Irvine32.inc
.data
fullName BYTE "Bob Johnson",0
nameSize = ($ - fullName) - 2
.code
main PROC
    mov ECX,nameSize
    mov ESI,OFFSET fullName
Sum:
    mov EBX,[ESI+ECX]
    add EAX,EBX
    loop Sum
    exit
main ENDP
END main

So I am having an issue I just want to read one character from the string at a time and store it in EBX register then take the value of that character and keep a running sum in EAX.

Add together all of the ASCII codes of the characters of the string, using 8-bit unsigned arithmetic. Overflow is ignored. The final value is the checksum. For example, if the string is "Joe", then the ASCII values are 4A, 6F, 65. The sum is 11E.

Answer 1

INCLUDE Irvine32.inc
.data

fullName BYTE "Bob Johnson",0       ; String storing name
nameSize = ($ - fullName)   ; Variable storing length of name

.code
main PROC

    mov ECX,nameSize        ; Set counter for loop
    mov ESI,OFFSET fullName ; Set pointer at fullName variable
    mov EAX,0               ; Clear the EAX register
    mov EBX,0               ; Clear the EBX register

Sum:                        ; Loop 

    mov bl,[ESI + ECX - 1]  ; Use the bl (8 bit register) to point at characters in the string.
    add EAX,EBX         ; Add the two registers together

    loop Sum                ; Loop  

    call DumpRegs           ; Display results

    exit
main ENDP

END main

SOLVED WOOT!!