本文解析了Linux内核中的键盘驱动程序，介绍了键盘中断处理程序的工作原理，包括按键扫描码到ASCII字符的转换过程、功能键处理及键盘状态更新等。
/*
* linux/kernel/keyboard.S
* #－－键盘驱动汇编程序，主要是键盘中断处理程序
* (C) 1991 Linus Torvalds
*/
/*
* Thanks to Alfred Leung for US keyboard patches
* Wolfgang Thiel for German keyboard patches
* Marc Corsini for the French keyboard
*/
/* KBD_FINNISH for Finnish keyboards
* KBD_US for US-type
* KBD_GR for German keyboards
* KBD_FR for Frech keyboard
*/
#define KBD_FINNISH
.text
.globl _keyboard_interrupt
/*
* these are for the keyboard read functions
*/
size = 1024 /* must be a power of two ! And MUST be the same
as in tty_io.c !!!! */
head = 4
tail = 8
proc_list = 12
buf = 16
mode: .byte 0 /* caps, alt, ctrl and shift mode */
leds: .byte 2 /* num-lock, caps, scroll-lock mode (nom-lock on) */
e0: .byte 0
/*
* con_int is the real interrupt routine that reads the
* keyboard scan-code and converts it into the appropriate
* ascii character(s).
*/ #－－键盘中断处理程序入口点
_keyboard_interrupt:
pushl %eax
pushl %ebx
pushl %ecx
pushl %edx
push %ds
push %es
movl $0x10,%eax
mov %ax,%ds
mov %ax,%es
movl _blankinterval,%eax
movl %eax,_blankcount
xorl %eax,%eax /* %eax is scan code */
inb $0x60,%al #－－从0x60端口读取当前按键的扫描码
cmpb $0xe0,%al #－－判断是否是0xe0和0xe1两个特殊扫描码
je set_e0
cmpb $0xe1,%al
je set_e1
call key_table(,%eax,4) #－－调用处理程序
movb $0,e0
e0_e1: inb $0x61,%al #－－针对8255A的PC标准键盘电路进行硬件复位处理
jmp 1f #－－对收到的扫描码作出应答，方法是首先禁止键盘，然后立刻重新允许键盘工作
1: jmp 1f
1: orb $0x80,%al #－－al位7置位，禁止键盘工作
jmp 1f
1: jmp 1f
1: outb %al,$0x61
jmp 1f
1: jmp 1f
1: andb $0x7F,%al
outb %al,$0x61 #－－允许键盘工作
movb $0x20,%al
outb %al,$0x20
pushl $0
call _do_tty_interrupt
addl $4,%esp
pop %es
pop %ds
popl %edx
popl %ecx
popl %ebx
popl %eax
iret
set_e0: movb $1,e0
jmp e0_e1
set_e1: movb $2,e0
jmp e0_e1
/*
* This routine fills the buffer with max 8 bytes, taken from
* %ebx:%eax. (%edx is high). The bytes are written in the
* order %al,%ah,%eal,%eah,%bl,%bh ... until %eax is zero.
*/
put_queue: #－－下面子程序把ebx:eax中的最多8个字符添入缓冲队列中
pushl %ecx
pushl %edx
movl _table_list,%edx # read-queue for console
movl head(%edx),%ecx
1: movb %al,buf(%edx,%ecx)
incl %ecx
andl $size-1,%ecx
cmpl tail(%edx),%ecx # buffer full - discard everything
je 3f
shrdl $8,%ebx,%eax
je 2f
shrl $8,%ebx
jmp 1b
2: movl %ecx,head(%edx)
movl proc_list(%edx),%ecx
testl %ecx,%ecx
je 3f
movl $0,(%ecx)
3: popl %edx
popl %ecx
ret
#－－键跳转表key_table中指针对应的各个按键（松键）处理子程序
ctrl: movb $0x04,%al #－－处理ctrl和alt
jmp 1f
alt: movb $0x10,%al
1: cmpb $0,e0
je 2f
addb %al,%al
2: orb %al,mode
ret
unctrl: movb $0x04,%al
jmp 1f
unalt: movb $0x10,%al
1: cmpb $0,e0
je 2f
addb %al,%al
2: notb %al
andb %al,mode
ret
lshift: #－－处理lshift和rshift
orb $0x01,mode
ret
unlshift:
andb $0xfe,mode
ret
rshift:
orb $0x02,mode
ret
unrshift:
andb $0xfd,mode
ret
caps: testb $0x80,mode #－－处理caps
jne 1f
xorb $4,leds
xorb $0x40,mode
orb $0x80,mode
set_leds:
call kb_wait
movb $0xed,%al /* set leds command */
outb %al,$0x60
call kb_wait
movb leds,%al
outb %al,$0x60
ret
uncaps: andb $0x7f,mode
ret
scroll:
testb $0x03,mode
je 1f
call _show_mem
jmp 2f
1: call _show_state
2: xorb $1,leds
jmp set_leds
num: xorb $2,leds
jmp set_leds
/*
* curosr-key/numeric keypad cursor keys are handled here.
* checking for numeric keypad etc.
*/ #－－处理方向键，数字小键盘方向键，检测数字小键盘
cursor:
subb $0x47,%al
jb 1f
cmpb $12,%al
ja 1f
jne cur2 /* check for ctrl-alt-del */
testb $0x0c,mode
je cur2
testb $0x30,mode
jne reboot
cur2: cmpb $0x01,e0 /* e0 forces cursor movement */
je cur
testb $0x02,leds /* not num-lock forces cursor */
je cur
testb $0x03,mode /* shift forces cursor */
jne cur
xorl %ebx,%ebx
movb num_table(%eax),%al
jmp put_queue
1: ret
#－－处理光标移动或插入删除按键
cur: movb cur_table(%eax),%al
cmpb $'9,%al
ja ok_cur
movb $'~,%ah
ok_cur: shll $16,%eax
movw $0x5b1b,%ax
xorl %ebx,%ebx
jmp put_queue
#if defined(KBD_FR)
num_table: #－－数字小键盘对应的数字ASCII码表
.ascii "789 456 1230."
#else
num_table:
.ascii "789 456 1230,"
#endif
cur_table: #－－小键盘上方向键或插入删除键对应的移动表示字符表
.ascii "HA5 DGC YB623"
/*
* this routine handles function keys
*/ #－－处理功能键
func: #－－把功能键扫描码变成转义字符序列存放到读队列中
subb $0x3B,%al #－－F1--F12
jb end_func
cmpb $9,%al
jbe ok_func
subb $18,%al
cmpb $10,%al
jb end_func
cmpb $11,%al
ja end_func
ok_func:
testb $0x10,mode
jne alt_func
cmpl $4,%ecx /* check that there is enough room */
jl end_func
movl func_table(,%eax,4),%eax
xorl %ebx,%ebx
jmp put_queue
alt_func: #－－处理alt+Fn组合键
pushl %eax
call _change_console
popl %eax
end_func:
ret
/*
* function keys send F1:'esc [ [ A' F2:'esc [ [ B' etc.
*/
func_table: #－－功能键发送的扫描码
.long 0x415b5b1b,0x425b5b1b,0x435b5b1b,0x445b5b1b
.long 0x455b5b1b,0x465b5b1b,0x475b5b1b,0x485b5b1b
.long 0x495b5b1b,0x4a5b5b1b,0x4b5b5b1b,0x4c5b5b1b
#－－扫描码ASCII字符映射表
#if defined(KBD_FINNISH) #－－芬兰语
key_map:
.byte 0,27
.ascii "1234567890+'"
.byte 127,9
.ascii "qwertyuiop}"
.byte 0,13,0
.ascii "asdfghjkl|{"
.byte 0,0
.ascii "'zxcvbnm,.-"
.byte 0,'*,0,32 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte '-,0,0,0,'+ /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '<
.fill 10,1,0
shift_map: #－－shift键被同时按下时的映射表
.byte 0,27
.ascii "!/"#$%&/()=?`"
.byte 127,9
.ascii "QWERTYUIOP]^"
.byte 13,0
.ascii "ASDFGHJKL//["
.byte 0,0
.ascii "*ZXCVBNM;:_"
.byte 0,'*,0,32 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte '-,0,0,0,'+ /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '>
.fill 10,1,0
alt_map: #－－alt键被同时按下时的映射表
.byte 0,0
.ascii "/0@/0$/0/0{[]}///0"
.byte 0,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte '~,13,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte 0,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte 0,0,0,0 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte 0,0,0,0,0 /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '|
.fill 10,1,0
#elif defined(KBD_US)
key_map: #－－美式键盘
.byte 0,27
.ascii "1234567890-="
.byte 127,9
.ascii "qwertyuiop[]"
.byte 13,0
.ascii "asdfghjkl;'"
.byte '`,0
.ascii "//zxcvbnm,./"
.byte 0,'*,0,32 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte '-,0,0,0,'+ /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '<
.fill 10,1,0
shift_map:
.byte 0,27
.ascii "!@#$%^&*()_+"
.byte 127,9
.ascii "QWERTYUIOP{}"
.byte 13,0
.ascii "ASDFGHJKL:/""
.byte '~,0
.ascii "|ZXCVBNM<>?"
.byte 0,'*,0,32 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte '-,0,0,0,'+ /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '>
.fill 10,1,0
alt_map:
.byte 0,0
.ascii "/0@/0$/0/0{[]}///0"
.byte 0,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte '~,13,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte 0,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte 0,0,0,0 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte 0,0,0,0,0 /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '|
.fill 10,1,0
#elif defined(KBD_GR) #－－德语键盘
key_map:
.byte 0,27
.ascii "1234567890//'"
.byte 127,9
.ascii "qwertzuiop@+"
.byte 13,0
.ascii "asdfghjkl[]^"
.byte 0,'#
.ascii "yxcvbnm,.-"
.byte 0,'*,0,32 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte '-,0,0,0,'+ /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '<
.fill 10,1,0
shift_map:
.byte 0,27
.ascii "!/"#$%&/()=?`"
.byte 127,9
.ascii "QWERTZUIOP//*"
.byte 13,0
.ascii "ASDFGHJKL{}~"
.byte 0,''
.ascii "YXCVBNM;:_"
.byte 0,'*,0,32 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte '-,0,0,0,'+ /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '>
.fill 10,1,0
alt_map:
.byte 0,0
.ascii "/0@/0$/0/0{[]}///0"
.byte 0,0
.byte '@,0,0,0,0,0,0,0,0,0,0
.byte '~,13,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte 0,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte 0,0,0,0 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte 0,0,0,0,0 /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '|
.fill 10,1,0
#elif defined(KBD_FR) #－－法语键盘
key_map:
.byte 0,27
.ascii "&{/"'(-}_/@)="
.byte 127,9
.ascii "azertyuiop^$"
.byte 13,0
.ascii "qsdfghjklm|"
.byte '`,0,42 /* coin sup gauche, don't know, [*|mu] */
.ascii "wxcvbn,;:!"
.byte 0,'*,0,32 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte '-,0,0,0,'+ /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '<
.fill 10,1,0
shift_map:
.byte 0,27
.ascii "1234567890]+"
.byte 127,9
.ascii "AZERTYUIOP<>"
.byte 13,0
.ascii "QSDFGHJKLM%"
.byte '~,0,'#
.ascii "WXCVBN?.///"
.byte 0,'*,0,32 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte '-,0,0,0,'+ /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '>
.fill 10,1,0
alt_map:
.byte 0,0
.ascii "/0~#{[|`//^@]}"
.byte 0,0
.byte '@,0,0,0,0,0,0,0,0,0,0
.byte '~,13,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte 0,0
.byte 0,0,0,0,0,0,0,0,0,0,0
.byte 0,0,0,0 /* 36-39 */
.fill 16,1,0 /* 3A-49 */
.byte 0,0,0,0,0 /* 4A-4E */
.byte 0,0,0,0,0,0,0 /* 4F-55 */
.byte '|
.fill 10,1,0
#else
#error "KBD-type not defined"
#endif
/*
* do_self handles "normal" keys, ie keys that don't change meaning
* and which have just one character returns.
*/
do_self:
lea alt_map,%ebx #－－首先根据mode标志选择alt_map,shift_map,key_map映射表之一
testb $0x20,mode /* alt-gr */
jne 1f
lea shift_map,%ebx
testb $0x03,mode
jne 1f
lea key_map,%ebx
1: movb (%ebx,%eax),%al #－－根据扫描码取映射表中对应的ASCII字符
orb %al,%al
je none
testb $0x4c,mode /* ctrl or caps */
je 2f
cmpb $'a,%al
jb 2f
cmpb $'},%al
ja 2f
subb $32,%al
2: testb $0x0c,mode /* ctrl */
je 3f
cmpb $64,%al
jb 3f
cmpb $64+32,%al
jae 3f
subb $64,%al
3: testb $0x10,mode /* left alt */
je 4f
orb $0x80,%al
4: andl $0xff,%eax
xorl %ebx,%ebx
call put_queue
none: ret
/*
* minus has a routine of it's own, as a 'E0h' before
* the scan code for minus means that the numeric keypad
* slash was pushed.
*/
minus: cmpb $1,e0
jne do_self
movl $'/,%eax
xorl %ebx,%ebx
jmp put_queue
/*
* This table decides which routine to call when a scan-code has been
* gotten. Most routines just call do_self, or none, depending if
* they are make or break.
*/
key_table: #－－这是子程序地址跳转表，当取得扫描码后就根据此表调用相应的扫描码处理子程序
.long none,do_self,do_self,do_self /* 00-03 s0 esc 1 2 */
.long do_self,do_self,do_self,do_self /* 04-07 3 4 5 6 */
.long do_self,do_self,do_self,do_self /* 08-0B 7 8 9 0 */
.long do_self,do_self,do_self,do_self /* 0C-0F + ' bs tab */
.long do_self,do_self,do_self,do_self /* 10-13 q w e r */
.long do_self,do_self,do_self,do_self /* 14-17 t y u i */
.long do_self,do_self,do_self,do_self /* 18-1B o p } ^ */
.long do_self,ctrl,do_self,do_self /* 1C-1F enter ctrl a s */
.long do_self,do_self,do_self,do_self /* 20-23 d f g h */
.long do_self,do_self,do_self,do_self /* 24-27 j k l | */
.long do_self,do_self,lshift,do_self /* 28-2B { para lshift , */
.long do_self,do_self,do_self,do_self /* 2C-2F z x c v */
.long do_self,do_self,do_self,do_self /* 30-33 b n m , */
.long do_self,minus,rshift,do_self /* 34-37 . - rshift * */
.long alt,do_self,caps,func /* 38-3B alt sp caps f1 */
.long func,func,func,func /* 3C-3F f2 f3 f4 f5 */
.long func,func,func,func /* 40-43 f6 f7 f8 f9 */
.long func,num,scroll,cursor /* 44-47 f10 num scr home */
.long cursor,cursor,do_self,cursor /* 48-4B up pgup - left */
.long cursor,cursor,do_self,cursor /* 4C-4F n5 right + end */
.long cursor,cursor,cursor,cursor /* 50-53 dn pgdn ins del */
.long none,none,do_self,func /* 54-57 sysreq ? < f11 */
.long func,none,none,none /* 58-5B f12 ? ? ? */
.long none,none,none,none /* 5C-5F ? ? ? ? */
.long none,none,none,none /* 60-63 ? ? ? ? */
.long none,none,none,none /* 64-67 ? ? ? ? */
.long none,none,none,none /* 68-6B ? ? ? ? */
.long none,none,none,none /* 6C-6F ? ? ? ? */
.long none,none,none,none /* 70-73 ? ? ? ? */
.long none,none,none,none /* 74-77 ? ? ? ? */
.long none,none,none,none /* 78-7B ? ? ? ? */
.long none,none,none,none /* 7C-7F ? ? ? ? */
.long none,none,none,none /* 80-83 ? br br br */
.long none,none,none,none /* 84-87 br br br br */
.long none,none,none,none /* 88-8B br br br br */
.long none,none,none,none /* 8C-8F br br br br */
.long none,none,none,none /* 90-93 br br br br */
.long none,none,none,none /* 94-97 br br br br */
.long none,none,none,none /* 98-9B br br br br */
.long none,unctrl,none,none /* 9C-9F br unctrl br br */
.long none,none,none,none /* A0-A3 br br br br */
.long none,none,none,none /* A4-A7 br br br br */
.long none,none,unlshift,none /* A8-AB br br unlshift br */
.long none,none,none,none /* AC-AF br br br br */
.long none,none,none,none /* B0-B3 br br br br */
.long none,none,unrshift,none /* B4-B7 br br unrshift br */
.long unalt,none,uncaps,none /* B8-BB unalt br uncaps br */
.long none,none,none,none /* BC-BF br br br br */
.long none,none,none,none /* C0-C3 br br br br */
.long none,none,none,none /* C4-C7 br br br br */
.long none,none,none,none /* C8-CB br br br br */
.long none,none,none,none /* CC-CF br br br br */
.long none,none,none,none /* D0-D3 br br br br */
.long none,none,none,none /* D4-D7 br br br br */
.long none,none,none,none /* D8-DB br ? ? ? */
.long none,none,none,none /* DC-DF ? ? ? ? */
.long none,none,none,none /* E0-E3 e0 e1 ? ? */
.long none,none,none,none /* E4-E7 ? ? ? ? */
.long none,none,none,none /* E8-EB ? ? ? ? */
.long none,none,none,none /* EC-EF ? ? ? ? */
.long none,none,none,none /* F0-F3 ? ? ? ? */
.long none,none,none,none /* F4-F7 ? ? ? ? */
.long none,none,none,none /* F8-FB ? ? ? ? */
.long none,none,none,none /* FC-FF ? ? ? ? */
/*
* kb_wait waits for the keyboard controller buffer to empty.
* there is no timeout - if the buffer doesn't empty, we hang.
*/
kb_wait: #－－等待键盘控制器缓冲空。若永不为空，则死掉。
pushl %eax
1: inb $0x64,%al
testb $0x02,%al
jne 1b
popl %eax
ret
/*
* This routine reboots the machine by asking the keyboard
* controller to pulse the reset-line low.
*/
reboot: #－－通过设置键盘控制器，向复位线输出负脉冲，使系统复位重启
call kb_wait
movw $0x1234,0x472 /* don't do memory check */
movb $0xfc,%al /* pulse reset and A20 low */
outb %al,$0x64
die: jmp die
|xGv00|fcc8d4de8197f69fde70263fb4d52380
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