就像是
char p = 'P';
int main()
{
__asm__ __volatile__
(
" movl $1, %%edx \n\t"
" leal p , %%ecx \n\t"
" movl $0, %%ebx \n\t"
" movl $4, %%eax \n\t"
" int $0x80 \n\t"
::: "%eax", "%ebx", "%ecx", "%edx"
);
}
:请注意,我曾经lea
将char的有效地址加载到ecx
寄存器中;对于ebx
我尝试$ 0和$ 1的价值,它似乎仍然可以工作…
int main()
{
__asm__ __volatile__
(
" movl $1, %%edx \n\t"
" subl $4, %%esp \n\t"
" movl $80, (%%esp)\n\t"
" movl %%esp, %%ecx \n\t"
" movl $1, %%ebx \n\t"
" movl $4, %%eax \n\t"
" int $0x80 \n\t"
" addl $4, %%esp\n\t"
::: "%eax", "%ebx", "%ecx", "%edx"
);
}
注意:它之所以有效是因为Intel处理器的字节序!:D