; ----------------------------------------------------------------------------- 
; 64-bit program that treats all its command line arguments as floating point  
; number and displays their average as a floating point number.  This program  
; uses a data section to store intermediate results, not that it has to, but  
; only to illustrate how data sections are used. 
; ----------------------------------------------------------------------------- 
global  main 

extern  atof
extern  printf 

section .data 
count:  dq 0 
sum:    dq 0 
format: db "%g", 10, 0 
error:  db "There are no cmds to average", 10, 0 

section .text 
main: 
        sub     rsp,8
        dec     rdi                     ;argc-1, da wir den programm namen ignorieren 
        jz      nothingToAverage        ;wenn rdi == 0 
        mov     [count], rdi            ;speichere args in [count]
        pxor    xmm8,xmm8
accumulate: 
        push    rdi                     ;sichere reg vor atoi aufruf 
        push    rsi 
        mov     rdi, [rsi+rdi*8]        ;argv[rdi] c alignment beachten! 
        call    atof                    ;rax enthält den wert von arg 
        pop     rsi                     ;wiederherstellen der reg nach 
        pop     rdi                     ;aufruf von atoi 
        addpd   xmm8,xmm0               ;summieren der werte
        dec     rdi                     ;argc runterzählen 
        jnz     accumulate              ;wiederhole wen argc != 0 
average: 
        movq    xmm0,xmm8
        movq    xmm1,[count]
        cvtsi2sd xmm1,[count]
        divsd   xmm0, xmm1              
        mov     rdi, format             ;erste arg für printf 
        mov     rax, 1                  ;printf hat var args es gibt 1 nicht 
        call    printf                  ;printf(format, sum/count) 
        add     rsp, 8                  ;wiederherstellen des stackpointers 
        ret

nothingToAverage: 
        mov     rdi, error 
        xor     rax, rax 
        call    printf 
        add     rsp,8
        ret