Untitled

        .file   "mystrlen.c"
        .text
.globl mystrlen
        .type   mystrlen, @function
mystrlen:
        movq    $1 , %rax       # set return value to 0 

while:
        movq    (%rdi), %rcx    # read bytes from memory

        cmpb    $0 , %ch        # compares value pointed to by first arg to zero 
        je      end             # return if value is zero 

        addq    $1, %rax        # value isn't zero so add 1 to the main counter
        addq    $1, %rdi        # increment string pointer by 1
        jmp     while           # return to beginning of loop
end:
        ret 


## THIS WORKS EXCEPT WHEN STRING HAS LENGTH 0 APPARENTLY