7

去年 1 月,我将 x86 组装作为一种爱好,因此我可以制作适用于 PCj 和 Tandy 1000 等老式 8086 计算机的游戏,但我发现的书籍并没有确切地教授该特定主题的内容。虽然一些 dos 和 bios 中断可以完成这项工作,但它们远非完美。

我的主要问题是在不停止程序的情况下读取按键的键盘状态。我找到了一些方法,但它们非常有限。INT 21h, AH 0Ch 读取最后按下的键,但以文本版本的方式。它不仅一次只能读取一个键,而且类似记事本的命中检测功能也使得无法知道该键被按住了多长时间。在我的谷歌旅行期间,我还看到了对端口 60h 到 64h 的引用,但仅此而已。实际的解释和工作代码几乎不存在。或者,也许我只是不擅长使用搜索引擎。

我需要知道的是一个键是否被按下。最好的解决方案是拥有所有键盘键的缓冲区/数组并读取其状态;1 表示已关闭,0 表示未关闭。或者只是访问最后一个被击中和释放的键的列表会很好(当然,有一种方法可以清除该缓冲区)。谁能指出我正确的方向?

编辑:首先,我应该提到我使用 Borland TASM。现在我编译了你的代码,它运行良好,尽管我几乎羞于承认我不理解其中的一半。我试图让它与 TASM 兼容,但它所做的只是在屏幕上创建垃圾并冻结。

这就是我想出的;

.MODEL TINY
.STACK 256

.DATA
kbdbuf DB 128 DUP (0)

msg1 db "Press and hold ESC", 13, 10, "$"
msg2 db "ESC pressed, release ESC", 13, 10, "$"
msg3 db "ESC released", 13, 10, "$"

.CODE
main PROC
    org 0100h
    mov ax, @data
    mov ds, ax

    xor     ax, ax
    mov     es, ax

    cli                         ; update ISR address w/ ints disabled
    push    word [es:9*4+2]     ; preserve ISR address
    push    word [es:9*4]
    lea si, irq1isr
    mov     word [es:9*4], si   ; requires a register
    mov     [es:9*4+2],cs
    sti

        mov     ah, 9
        lea     dx, msg1
        int     021h                ; print "Press and hold ESC"

    test1:
        mov     al, [kbdbuf + 1]    ; check Escape key state (Esc scan code = 1)
        or      al, al
        jz      test1               ; wait until it's nonzero (pressed/held)

        lea     dx, msg2
        int     021h                ; print "ESC pressed, release ESC"

    test2:
        mov     al, [kbdbuf + 1]    ; check Escape key state (Esc scan code = 1)
        or      al, al
        jnz     test2               ; wait until it's zero (released/not pressed)

        lea     dx, msg3            ; print "ESC released"
        int     021h

    cli                         ; update ISR address w/ ints disabled
    pop     word [es:9*4]       ; restore ISR address
    pop     word [es:9*4+2]
    sti

    ret

    irq1isr:
    push    ax bx

    ; read keyboard scan code
    in      al, 060h

    ; update keyboard state
    xor     bh, bh
    mov     bl, al
    and     bl, 07Fh            ; bx = scan code
    shr     al, 7               ; al = 0 if pressed, 1 if released
    xor     al, 1               ; al = 1 if pressed, 0 if released
    mov     [cs:bx+kbdbuf], al

    ; send EOI to XT keyboard
    in      al, 061h
    mov     ah, al
    or      al, 080h
    out     061h, al
    mov     al, ah
    out     061h, al

    ; send EOI to master PIC
    mov     al, 020h
    out     020h, al

    pop     bx ax
    iret
main ENDP

END main

我不确定我是否正确编码了中断。如果我知道端口 060h - 064h 是如何工作的,那就见鬼了。

4

3 回答 3

3

以下是您的操作方法:

; compile with NASM: nasm.exe -f bin kbd.asm -o kbd.com

bits 16
org 0x100

    xor     ax, ax
    mov     es, ax

    cli                         ; update ISR address w/ ints disabled
    push    word [es:9*4+2]     ; preserve ISR address
    push    word [es:9*4]
    mov     word [es:9*4], irq1isr
    mov     [es:9*4+2],cs
    sti

    call    test

    cli                         ; update ISR address w/ ints disabled
    pop     word [es:9*4]       ; restore ISR address
    pop     word [es:9*4+2]
    sti

    ret

test:
    mov     ah, 9
    mov     dx, msg1
    int     0x21                ; print "Press and hold ESC"

test1:
    mov     al, [kbdbuf + 1]    ; check Escape key state (Esc scan code = 1)
    or      al, al
    jz      test1               ; wait until it's nonzero (pressed/held)

    mov     dx, msg2
    int     0x21                ; print "ESC pressed, release ESC"

test2:
    mov     al, [kbdbuf + 1]    ; check Escape key state (Esc scan code = 1)
    or      al, al
    jnz     test2               ; wait until it's zero (released/not pressed)

    mov     dx, msg3            ; print "ESC released"
    int     0x21

    ret

irq1isr:
    pusha

    ; read keyboard scan code
    in      al, 0x60

    ; update keyboard state
    xor     bh, bh
    mov     bl, al
    and     bl, 0x7F            ; bx = scan code
    shr     al, 7               ; al = 0 if pressed, 1 if released
    xor     al, 1               ; al = 1 if pressed, 0 if released
    mov     [cs:bx+kbdbuf], al

    ; send EOI to XT keyboard
    in      al, 0x61
    mov     ah, al
    or      al, 0x80
    out     0x61, al
    mov     al, ah
    out     0x61, al

    ; send EOI to master PIC
    mov     al, 0x20
    out     0x20, al

    popa
    iret

kbdbuf:
    times   128 db 0

msg1 db "Press and hold ESC", 13, 10, "$"
msg2 db "ESC pressed, release ESC", 13, 10, "$"
msg3 db "ESC released", 13, 10, "$"

在 DOS/Win9x/NT/2K/XP/32-bit Vista/7 或 DosBox 中运行它。

更新: TASM 版本:

; file: kbdt.asm
; compile with TASM/TLINK:
;   tasm.exe kbdt.asm
;   tlink.exe /t kbdt.obj

.286

code segment use16
assume cs:code, ds:code, ss:code
org 100h

main:
    xor     ax, ax
    mov     es, ax

    cli                         ; update ISR address w/ ints disabled
    push    word ptr es:[9*4+2]     ; preserve ISR address
    push    word ptr es:[9*4]
    mov     word ptr es:[9*4], offset irq1isr
    mov     es:[9*4+2],cs
    sti

    call    test0

    cli                         ; update ISR address w/ ints disabled
    pop     word ptr es:[9*4]   ; restore ISR address
    pop     word ptr es:[9*4+2]
    sti

    ret

test0:
    mov     ah, 9
    mov     dx, offset msg1
    int     21h                 ; print "Press and hold ESC"

test1:
    mov     al, [kbdbuf + 1]    ; check Escape key state (Esc scan code = 1)
    or      al, al
    jz      test1               ; wait until it's nonzero (pressed/held)

    mov     dx, offset msg2
    int     21h                 ; print "ESC pressed, release ESC"

test2:
    mov     al, [kbdbuf + 1]    ; check Escape key state (Esc scan code = 1)
    or      al, al
    jnz     test2               ; wait until it's zero (released/not pressed)

    mov     dx, offset msg3     ; print "ESC released"
    int     21h

    ret

irq1isr:
    pusha

    ; read keyboard scan code
    in      al, 60h

    ; update keyboard state
    xor     bh, bh
    mov     bl, al
    and     bl, 7Fh             ; bx = scan code
    shr     al, 7               ; al = 0 if pressed, 1 if released
    xor     al, 1               ; al = 1 if pressed, 0 if released
    mov     cs:[bx+kbdbuf], al

    ; send EOI to XT keyboard
    in      al, 61h
    mov     ah, al
    or      al, 80h
    out     61h, al
    mov     al, ah
    out     61h, al

    ; send EOI to master PIC
    mov     al, 20h
    out     20h, al

    popa
    iret

kbdbuf      db 128 dup (0)

msg1 db "Press and hold ESC", 13, 10, "$"
msg2 db "ESC pressed, release ESC", 13, 10, "$"
msg3 db "ESC released", 13, 10, "$"

code ends

end main
于 2012-05-09T23:08:36.907 回答
0

通常对于像这样的旧系统,人们使用 BIOS 有点像预先提供的一组库函数,其中只有在方便时才使用键盘功能等功能。在您的情况下,BIOS 键盘服务不方便,因此您不要使用它们。

相反,您想用自己的键盘中断处理程序替换 BIOS 键盘中断处理程序并实现自己的键盘驱动程序。键盘使用 IRQ1,即中断 9。中断向量表从 0x0000:0x0000 开始,因此您希望在 0x0000:9*4 = 0x0000:0x0024 处获取 4 个字节并将它们存储在某处(这样您就可以将它们放回去当您的软件退出时恢复正常)并将您自己的键盘 IRQ 处理程序的地址(偏移然后段)放在那里。

要编写自己的键盘驱动程序,首先要了解涉及到 2 个硬件。计算机中有键盘控制器芯片(或“PS/2 控制器”),它(通过串行通信)与键盘本身内部的芯片通信。

有关键盘控制器芯片的信息,请参见http://wiki.osdev.org/%228042%22_PS/2_Controller

有关键盘本身内部芯片的信息,请参阅http://wiki.osdev.org/PS/2_Keyboard

于 2012-05-09T22:44:19.227 回答
0

使用端口 60h 和端口 64h 轮询键盘的示例:

       cli            ; stop software-Interrupts
       mov  al, 2     ; stop IRQ 1
       out  21h, al
       sti
P1:
       in   al, 64h     ; get Status
       test al, 1       ;  is there something in the outputbuffer?
       jz  P1
       test al, 20h     ;  it is a byte from the PS2-Mouse?
       jnz  P1
       in   al, 60h     ; get a key
       cmp  al, 1       ;  Escape-key?
       jz  XRAUS        ; then goto end
;───────────────────────────────────────────────────────────────
       mov  si, OFFSET SONTAB  ; get the offsetaddress of our special-key table
       mov  cl, Extablen       ; lenght
XSUCH: cmp  al, [si]
       jz  XFOUND
       lea  si, [si+1]         ; instead of "inc si"
       dec  cl
       jnz XSUCH
;───────────────────────────────────────────────────────────────
       mov  si, OFFSET TASTTAB  ; get the offsetaddress of our key table
       mov  cx, tablen
       mov  bx, OFFSET TEXTTAB  ; our corresponding ASCII table
SUCH:  cmp  al, [si]
       jz  short FOUND
       lea  si, [si+1]
       dec  cx
       jnz SUCH
       jmp  P1
;───────────────────────────────────────────────────────────────
XRAUS: in   al, 60h ; clear outputbuffer
       cli
       xor  al, al  ; enable IRQ 1
       out  21h, al
       sti
       mov  ah, 1  ; clear buffer in the ram
       int  16h
; ...some more instructions
;───────────────────────────────────────────────────────────────
FOUND:  mov  si, tablen   ; Length
        sub  si, cx
        xor  ecx, ecx
        mov  cl, [bx+si]  ; get the ASCII from our table
;  ...some more instructions
;───────────────────────────────────────────────────────────────
XFOUND:
;  Tab,shift li.,shift re.,HOME,UP,LEFT,RIGHT,END,DOWN
        cmp  cl, 1       ; DOWN-key
        jnz short  ...   ; jump to next
        ....
        ....
        cmp  cl, 9       ; Tab-key
        jnz  P1
;  ...some more instructions
:------------------------Data area----------------------
TASTTAB DB 02h,03h,04h,05h,06h,07h,08h,09h,0Ah,0Bh,0Ch,0Dh
        DB 10h,11h,12h,13h,14h,15h,16h,17h,18h,19h,1Ah,1Bh,1Eh,1Fh
        DB 20h,21h,22h,23h,24h,25h,26h,27h,28h,29h,2Bh,2Ch,2Dh,2Eh,2Fh
        DB 30h,31h,32h,33h,34h,35h,39h
        DB 56h
tablen =  ($-TASTTAB)
TEXTTAB DB "1234567890ß'"     ; with some german letters inside
        DB "qwertzuiopü+as"
        DB "dfghjklöä^#yxcv"
        DB "bnm,.- "
        DB "<"
Textablen  =  ($-TEXTTAB)
;---------------------------------------------------------------------------
;  Tab,shift left.,shift rigth.,HOME,UP,LEFT,RIGHT,END,DOWN
;----------
SONTAB  DB 0Fh,2Ah,36h,47h,48h,4Bh,4Dh,4Fh,50h
Extablen  =  ($-SONTAB)
        DB 0,0,0 ; for data_alignment of following entries
于 2014-01-07T09:49:32.063 回答