1 ; loopint_64.asm code loopint.c for nasm
2 ; /* loopint_64.c a very simple loop that will be coded for nasm */
3 ; #include <stdio.h>
4 ; int main()
5 ; {
6 ; long int dd1[100]; // 100 could be 3 gigabytes
7 ; long int i; // must be long for more than 2 gigabytes
8 ; dd1[0]=5; /* be sure loop stays 1..98 */
9 ; dd1[99]=9;
10 ; for(i=1; i<99; i++) dd1[i]=7;
11 ; printf("dd1[0]=%ld, dd1[1]=%ld, dd1[98]=%ld, dd1[99]=%ld\n",
12 ; dd1[0], dd1[1], dd1[98],dd1[99]);
13 ; return 0;
14 ;}
15 ; execution output is dd1[0]=5, dd1[1]=7, dd1[98]=7, dd1[99]=9
16
17 section .bss
18 00000000 <res 00000320> dd1: resq 100 ; reserve 100 long int
19 00000320 <res 00000008> i: resq 1 ; actually unused, kept in register
20
21 section .data ; Data section, initialized variables
22 00000000 6464315B305D3D256C- fmt: db "dd1[0]=%ld, dd1[1]=%ld, dd1[98]=%ld, dd1[99]=%ld",10,0
23 00000009 642C206464315B315D-
24 00000012 3D256C642C20646431-
25 0000001B 5B39385D3D256C642C-
26 00000024 206464315B39395D3D-
27 0000002D 256C640A00
28
29 extern printf ; the C function, to be called
30
31 section .text
32 global main
33 00000000 55 main: push rbp ; set up stack
34
35 00000001 48C70425[00000000]- mov qword [dd1],5 ; dd1[0]=5; memory to memory
36 00000009 05000000
37 0000000D 48C70425[18030000]- mov qword [dd1+99*8],9 ; dd1[99]=9; indexed 99 qword
38 00000015 09000000
39
40 00000019 BF08000000 mov rdi, 1*8 ; i=1; index, will move by 8 bytes
41 0000001E 48C787[00000000]07- loop1: mov qword [dd1+rdi],7 ; dd1[i]=7;
42 00000026 000000
43 00000029 4883C708 add rdi, 8 ; i++; 8 bytes
44 0000002D 4881FF18030000 cmp rdi, 8*99 ; i<99
45 00000034 75E8 jne loop1 ; loop until incremented i=99
46
47 00000036 48BF- mov rdi, fmt ; pass address of format
48 00000038 [0000000000000000]
49 00000040 488B3425[00000000] mov rsi, qword [dd1] ; dd1[0] first list parameter
50 00000048 488B1425[08000000] mov rdx, qword [dd1+1*8] ; dd1[1] second list parameter
51 00000050 488B0C25[10030000] mov rcx, qword [dd1+98*8] ; dd1[98] third list parameter
52 00000058 4C8B0425[18030000] mov r8, qword [dd1+99*8] ; dd1[99] fourth list parameter
53 00000060 B800000000 mov rax, 0 ; no xmm used
54 00000065 E8(00000000) call printf ; Call C function
55
56 0000006A 5D pop rbp ; restore stack
57 0000006B B800000000 mov rax,0 ; normal, no error, return value
58 00000070 C3 ret ; return 0;