这周和@whr 一起实现了Kestrel kernel的键盘响应，摒弃了原先使用的grub代码。 今天来总结一下代实现的关键
我们的核心汇编代码， 我来简单解读下
ENTRY(int21_handler)
cli /* 禁用中断 */
pushw %es
pushw %ds
pushl %eax
pushl %ecx
pushl %edx
pushl %ebx
pushl %esp
pushl %ebp
pushl %esi
pushl %edi /* 入栈， 保存现场 */
movb $0x61, %al
outb %al, $PIC0_OCW2 /* 使用0x61去复位键盘中断 */
xorl %eax, %eax /* 对eax寄存器清零 */
movw $0x0060, %dx /* Port 0x60 是对PS/2 进行 read/write 的 Data Port */
inb %dx, %al /* 从Port 0x60取出keycode到ax */
pushl %eax /* 保护keycode */
movw %ss, %ax
movw %ax, %ds
movw %ax, %es
call input_buffer_put
cli
popl %eax
popl %edi
popl %esi
popl %ebp
popl %esp
popl %ebx
popl %edx
popl %ecx
popl %eax
popw %ds
popw %es
sti /* 开启cpu中断 */
iret</pre></p>下面附上一些wiki.osdev.org的资料：</h3>
</p>PS/2 Controller IO Ports</span></p>
The PS/2 Controller itself uses 2 IO ports (IO ports 0x60 and 0x64). Like many IO ports, reads and writes may access completely different internal registers.
Historical note : The PC-XT PPI had used port 0x61 to reset the keyboard interrupt request signal (among other unrelated functions). Port 0x61 has no keyboard related functions on AT and PS/2 compatibles.
IO Port</th></p> Access Type</th></p> Purpose</th>
</tr></p>0x60</td></p> Read/Write</td></p> Data Port</td>
</tr></p>0x64</td></p> Read</td></p> Status Register</td>
</tr></p>0x64</td></p> Write</td></p> Command Register</td>
</tr>
</tbody>
</table>
关于通过keycode获取按键：</p>