int32_t execute(const uint8_t* command)
{	
	dentry_t fentry;
	int return_val = -1;
	
	if (-1 == read_dentry_by_name(command,&fentry)) {
		return -1;
	}
	
	asm  volatile (
		"movl %0 , %%eax\n\t" 
		"movl %%eax , %%CR3"	  
		: 
		: "r"(ppagedir)
		: "%eax"
	);
	
	copy_file(fentry);
	
	asm volatile (
		"pushl %2\n\t"
		"pushl %4\n\t"
		"pushl $0x0202 \n\t"
		"pushl %3\n\t"
		"pushl %0\n\t"
		"mov %2,%%ax\n\t"
		"mov %%ax,%%ds\n\t" 
		"iret"
		: 
		: "g"(tss.eip),"g"(tss.ebp),"g"(USER_DS),"g"(USER_CS),"g"(tss.esp)
		: "%eax"
	);
	return return_val;
}