Level : newbie

OS : linux
Language : C and inline ASM (GCC)

INTRODUCTION

those who started out coding assemly programs in windows and masm and then
started using msvc or bcc would find it almost a head ache to code
an inline assembly in gcc or even use the native as (gnu assembler)
because gcc natively uses AT&T syntax while windowers are accustomed to Intel Syntax

i now show you how to inline in gcc with intel_syntax directly embedded
this is a small Hello World Program that is coded in Assembly Using int 0x80

the code in c is as follows

#include <stdio>
#include <string.h>
char inlined[] = "this is a message from intel syntaxed inlined assembly code\n";
int len;
int main (void)
{
printf("this is a sample intel syntaxed and inlined c program\n");
len = strlen(inlined);
printf("%d\n",len);
asm(".intel_syntax noprefix\n");
asm("mov edx,len\n");
asm("mov ecx,offset inlined\n");
asm("mov ebx,1\n");
asm("mov eax,4\n");
asm("int 0x80\n");
printf("probably it is a success look in gdb\n");
return 1;

notice the first line :

asm(".intel_syntax noprefix\n");

someone@server:~/myfirst/myfirstasm> ./intelinlined
this is a sample intel syntaxed and inlined c program
60
this is a message from intel syntaxed inlined assembly code
probably it is a success look in gdb
someone@server:~/myfirst/myfirstasm>

„  ....... ! ;********************************************************                            „ 
„  ....... ! main:                           ;xref o80482c7                                       „ 
„  ....... !   push        ebp                                                                    „ 
„  804836d !   mov         ebp, esp                                                               „ 
„  804836f !   sub         esp, 8                                                                 „ 
„  8048372 !   and         esp, 0fffffff0h                                                        „ 
„  8048375 !   mov         eax, 0                                                                 „ 
„  804837a !   sub         esp, eax                                                               „ 
„  804837c !   sub         esp, 0ch                                                               „ 
„  804837f !   push        strz_this_is_a_sample_intel_syntax_8048520                             „ 
„  8048384 !   call        printf@@GLIBC_2.0                                                      „ 
„  8048389 !   add         esp, 10h                                                               „ 
„  804838c !   sub         esp, 0ch                                                               „ 
„  804838f !   push        inlined                                                                „ 
„  8048394 !   call        strlen@@GLIBC_2.0                                                      „ 
„  8048399 !   add         esp, 10h                                                               „ 
„  804839c !   mov         [len], eax                                                             „ 
„  80483a1 !   sub         esp, 8                                                                 „ 
„  80483a4 !   push        dword ptr [len]                                                        „ 
„  80483aa !   push        data_8048557                                                           „ 
„  80483af !   call        printf@@GLIBC_2.0                                                      „ 
„  80483b4 !   add         esp, 10h                                                               „ 
„  80483b7 !   mov         edx, [len]                                                             „ 
„  80483bd !   mov         ecx, inlined                                                           „ 
„  80483c2 !   mov         ebx, 1                                                                 „ 
„  80483c7 !   mov         eax, 4                                                                 „ 
„  80483cc !   int         80h                                                                    „ 
„  80483ce !   sub         esp, 0ch                                                               „ 
„  80483d1 !   push        strz_probably_it_is_a_success_look_8048560                             „ 
„  80483d6 !   call        printf@@GLIBC_2.0                                                      „ 
„  80483db !   add         esp, 10h                                                               „ 
„  80483de !   mov         eax, 1                                                                 „ 
„  80483e3 !   leave                                                                              „ 
„  80483e4 !   ret