我正在 NASM 程序集中编写操作系统，但在制作鼠标处理程序（指向设备 BIOS 接口处理程序）时遇到问题。我尝试在互联网上搜索如何做到这一点，但没有成功。
这是设置的代码：
call checkPS2 ;PS2 routines
jc NOMOUSE
call enablePS2
jc NOMOUSE
PS2 的功能如下：
;PS2 mouse routines
NOMOUSE:
;Prompt error
ret
checkPS2:
int 11h ; get equipment list
test al, 3
jz noPS2 ; jump if PS/2-Mouse not indicated
mov bh,3
mov ax, 0C205h
int 15h ; initialize mouse, bh=datasize
jc noPS2
mov bh,3
mov ax, 0C203h
int 15h ; set mouse resolution bh
jc noPS2
mov ax, cs
mov es, ax
mov bx, PS2dummy
mov ax, 0C207h
int 15h ; mouse, es:bx=ptr to handler
jc noPS2
xor bx, bx
mov es, bx ; mouse, es:bx=ptr to handler
mov ax, 0C207h
int 15h
ret
noPS2:
stc
ret
PS2dummy:
retf
enablePS2:
call disablePS2
mov ax, cs
mov es, ax
mov bx, IRQhandler
mov ax, 0C207h ; es:bx=ptr to handler
int 15h
mov bh,1 ; set mouse on
mov ax, 0C200h
int 15h
ret
disablePS2:
xor bx, bx ; set mouse off
mov ax, 0C200h
int 15h
xor bx, bx
mov es, bx
mov ax, 0C207h ; es:bx=ptr to handler
int 15h
ret
IRQhandler:
;assume ds:nothing,es:nothing
cld
push ds
push es
pusha
mov ax, cs
mov ds, ax
mov bp,sp
mov al,[bp+24+6] ; buttons
mov bl,al
shl al,3 ; CF=Y sign bit
sbb ch,ch ; signed extension 9->16 bit
cbw ; extend X sign bit
mov al,[bp+24+4] ; AX=X movement
mov cl,[bp+24+2] ; CX=Y movement
xchg bx,ax
neg cx ; reverse Y movement
popa
pop es
pop ds
retf
调用这些函数的循环：
mov ax, 0xc209 ;Reads from the mouse
int 15h ;-||-
mov dl, bl ;first byte(bl)
mov bl, 02h ;Color Green
call printhex ;prints dl in hex
mov ax, 0xc209 ;Reads from the mouse
int 15h ;-||-
mov dl, cl ;second byte(bl)
mov bl, 02h ;Color Green
call printhex ;prints dl in hex
mov ax, 0xc209 ;Reads from the mouse
int 15h ;-||-
mov bl, 02h ;Color Green
call printhex ;prints dl(3rd byte read)
我注意到的第一件事是屏幕上有许多随机出现的白色像素。
代码应该只给出鼠标的位置，而鼠标光标应保持隐藏状态。我已经测试过我的printhex函数，我知道它有效，我看到的数字是：
0x02
0x00
0x00
当我移动鼠标时，所有值都没有改变。我的配置是带有 PS/2 鼠标的 VirtualBox。
您没有提供完整的示例，但我终于有时间看一下这个。主要问题之一是INT 15h/AX=0C209h是一个可选功能。 RBIL 中有一条注释说
注意：IBM 将此功能归类为可选
我发现在许多模拟器（QEMU、BOCH、VirtualBox）上似乎没有实现此 BIOS 功能。调用它不会产生您正在寻找的数据。您可以使用鼠标处理程序读取 X 和 Y 移动和状态字节，并更新主例程可以轮询的全局变量。你的鼠标处理程序IRQhandler并不是真正的 IRQ 处理程序，而是 BIOS 鼠标中断处理程序将调用的 FAR 函数。该处理程序中有一些现有代码可检索 X 和 Y 运动，但不会对其执行任何操作。如果您维护 X 和 Y 的几个全局变量并向其中添加移动值，您可以维护主循环可以查询的绝对坐标。您还可以创建一个全局变量来存储读取的状态字节。
使用您的代码作为模板，我生成了这个简单的引导加载程序来测试此代码。引导加载程序包含一个BIOS 参数块如果您打算从使用软盘模拟的 USB在真实的硬件上。如果不需要，可以将其删除。我还提供了一些例程来以十六进制显示无符号字节和字。视频模式可以调整，但我使用模式 13h (320x200x256) 作为默认值：
bpb.inc:
global bpb_disk_info
jmp boot_start
TIMES 3-($-$$) DB 0x90 ; Support 2 or 3 byte encoded JMPs before BPB.
bpb_disk_info:
; Dos 4.0 EBPB 1.44MB floppy
OEMname: db "mkfs.fat" ; mkfs.fat is what OEMname mkdosfs uses
bytesPerSector: dw 512
sectPerCluster: db 1
reservedSectors: dw 1
numFAT: db 2
numRootDirEntries: dw 224
numSectors: dw 2880
mediaType: db 0xf0
numFATsectors: dw 9
sectorsPerTrack: dw 18
numHeads: dw 2
numHiddenSectors: dd 0
numSectorsHuge: dd 0
driveNum: db 0
reserved: db 0
signature: db 0x29
volumeID: dd 0x2d7e5a1a
volumeLabel: db "NO NAME "
fileSysType: db "FAT12 "
boot.asm:
HW_EQUIP_PS2 equ 4 ; PS2 mouse installed?
MOUSE_PKT_BYTES equ 3 ; Number of bytes in mouse packet
MOUSE_RESOLUTION equ 3 ; Mouse resolution 8 counts/mm
VIDEO_MODE equ 0x13
bits 16
cpu 8086
ORG 0x7c00
; Include a BPB (1.44MB floppy with FAT12) to be more compatible with USB floppy media
%include "bpb.inc"
boot_start:
xor ax, ax ; DS=SS=ES=0
mov ds, ax
mov ss, ax ; Stack at 0x0000:0x7c00
mov sp, 0x7c00
cld ; Set string instructions to use forward movement
; FAR JMP to ensure set CS to 0
jmp 0x0000:.setcs
.setcs:
mov ax, VIDEO_MODE
int 0x10 ; Set video mode
call mouse_initialize
jc .no_mouse ; If CF set then error, inform user and end
call mouse_enable ; Enable the mouse
sti
.main_loop:
hlt ; Halt processor until next interrupt
call poll_mouse ; Poll mouse and update display with coordintes & status
jmp .main_loop ; Endless main loop
.no_mouse:
mov si, noMouseMsg ; Error enabling mouse
call print_string ; Display message and enter infinite loop
.err_loop:
hlt
jmp .err_loop
; Function: mouse_initialize
; Initialize the mouse if present
;
; Inputs: None
; Returns: CF = 1 if error, CF=0 success
; Clobbers: AX
mouse_initialize:
push es
push bx
int 0x11 ; Get equipment list
test ax, HW_EQUIP_PS2 ; Is a PS2 mouse installed?
jz .no_mouse ; if not print error and end
mov ax, 0xC205 ; Initialize mouse
mov bh, MOUSE_PKT_BYTES ; 3 byte packets
int 0x15 ; Call BIOS to initialize
jc .no_mouse ; If not successful assume no mouse
mov ax, 0xC203 ; Set resolution
mov bh, MOUSE_RESOLUTION ; 8 counts / mm
int 0x15 ; Call BIOS to set resolution
jc .no_mouse ; If not successful assume no mouse
push cs
pop es ; ES = segment where code and mouse handler reside
mov bx, mouse_callback_dummy
mov ax, 0xC207 ; Install a default null handler (ES:BX)
int 0x15 ; Call BIOS to set callback
jc .no_mouse ; If not successful assume no mouse
clc ; CF=0 is success
jmp .finished
.no_mouse:
stc ; CF=1 is error
.finished:
pop bx
pop es
ret
; Function: mouse_enable
; Enable the mouse
;
; Inputs: None
; Returns: None
; Clobbers: AX
mouse_enable:
push es
push bx
call mouse_disable ; Disable mouse before enabling
push cs
pop es
mov bx, mouse_callback
mov ax, 0xC207 ; Set mouse callback function (ES:BX)
int 0x15 ; Call BIOS to set callback
mov ax, 0xC200 ; Enable/Disable mouse
mov bh, 1 ; BH = Enable = 1
int 0x15 ; Call BIOS to disable mouse
pop bx
pop es
ret
; Function: mouse_disable
; Disable the mouse
;
; Inputs: None
; Returns: None
; Clobbers: AX
mouse_disable:
push es
push bx
mov ax, 0xC200 ; Enable/Disable mouse
xor bx, bx ; BH = Disable = 0
int 0x15 ; Call BIOS to disable mouse
mov es, bx
mov ax, 0xC207 ; Clear callback function (ES:BX=0:0)
int 0x15 ; Call BIOS to set callback
pop bx
pop es
ret
; Function: mouse_callback (FAR)
; called by the interrupt handler to process a mouse data packet
; All registers that are modified must be saved and restored
; Since we are polling manually this handler does nothing
;
; Inputs: SP+4 = Unused (0)
; SP+6 = MovementY
; SP+8 = MovementX
; SP+10 = Mouse Status
;
; Returns: None
; Clobbers: None
ARG_OFFSETS equ 6 ; Offset of args from BP
mouse_callback:
push bp ; Function prologue
mov bp, sp
push ds ; Save registers we modify
push ax
push bx
push cx
push dx
push cs
pop ds ; DS = CS, CS = where our variables are stored
mov al,[bp+ARG_OFFSETS+6]
mov bl, al ; BX = copy of status byte
mov cl, 3 ; Shift signY (bit 5) left 3 bits
shl al, cl ; CF = signY
; Sign bit of AL = SignX
sbb dh, dh ; CH = SignY value set in all bits
cbw ; AH = SignX value set in all bits
mov dl, [bp+ARG_OFFSETS+2] ; CX = movementY
mov al, [bp+ARG_OFFSETS+4] ; AX = movementX
; new mouse X_coord = X_Coord + movementX
; new mouse Y_coord = Y_Coord + (-movementY)
neg dx
mov cx, [mouseY]
add dx, cx ; DX = new mouse Y_coord
mov cx, [mouseX]
add ax, cx ; AX = new mouse X_coord
; Status
mov [curStatus], bl ; Update the current status with the new bits
mov [mouseX], ax ; Update current virtual mouseX coord
mov [mouseY], dx ; Update current virtual mouseY coord
pop dx ; Restore all modified registers
pop cx
pop bx
pop ax
pop ds
pop bp ; Function epilogue
mouse_callback_dummy:
retf ; This routine was reached via FAR CALL. Need a FAR RET
; Function: poll_mouse
; Poll the mouse state and display the X and Y coordinates and the status byte
;
; Inputs: None
; Returns: None
; Clobbers: None
poll_mouse:
push ax
push bx
push dx
mov bx, 0x0002 ; Set display page to 0 (BH) and color green (BL)
cli
mov ax, [mouseX] ; Retrieve current mouse coordinates. Disable interrupts
mov dx, [mouseY] ; So that these two variables are read atomically
sti
call print_word_hex ; Print the mouseX coordinate
mov si, delimCommaSpc
call print_string
mov ax, dx
call print_word_hex ; Print the mouseY coordinate
mov si, delimCommaSpc
call print_string
mov al, [curStatus]
call print_byte_hex ; Print the last read mouse state byte
mov al, 0x0d
call print_char ; Print carriage return to return to beginning of line
pop dx
pop bx
pop ax
ret
; Function: print_string
; Display a string to the console on the specified page and in a
; specified color if running in a graphics mode
;
; Inputs: SI = Offset of address to print
; BH = Page number
; BL = foreground color (graphics modes only)
; Clobbers: SI
print_string:
push ax
mov ah, 0x0e ; BIOS TTY Print
jmp .getch
.repeat:
int 0x10 ; print character
.getch:
lodsb ; Get character from string
test al,al ; Have we reached end of string?
jnz .repeat ; if not process next character
.end:
pop ax
ret
; Function: print_char
; Print character on specified page and in a specified color
; if running in a graphics mode
;
; Inputs: AL = Character to print
; BH = Page number
; BL = foreground color (graphics modes only)
; Returns: None
; Clobbers: AX
print_char:
mov ah, 0x0e ; TTY function to display character in AL
int 0x10 ; Make BIOS call
ret
; Function: print_word_hex
; Print a 16-bit unsigned integer in hexadecimal on specified
; page and in a specified color if running in a graphics mode
;
; Inputs: AX = Unsigned 16-bit integer to print
; BH = Page number
; BL = foreground color (graphics modes only)
; Returns: None
; Clobbers: Mone
print_word_hex:
xchg al, ah ; Print the high byte first
call print_byte_hex
xchg al, ah ; Print the low byte second
call print_byte_hex
ret
; Function: print_byte_hex
; Print a 8-bit unsigned integer in hexadecimal on specified
; page and in a specified color if running in a graphics mode
;
; Inputs: AL = Unsigned 8-bit integer to print
; BH = Page number
; BL = foreground color (graphics modes only)
; Returns: None
; Clobbers: Mone
print_byte_hex:
push ax
push cx
push bx
lea bx, [.table] ; Get translation table address
; Translate each nibble to its ASCII equivalent
mov ah, al ; Make copy of byte to print
and al, 0x0f ; Isolate lower nibble in AL
mov cl, 4
shr ah, cl ; Isolate the upper nibble in AH
xlat ; Translate lower nibble to ASCII
xchg ah, al
xlat ; Translate upper nibble to ASCII
pop bx ; Restore attribute and page
mov ch, ah ; Make copy of lower nibble
mov ah, 0x0e
int 0x10 ; Print the high nibble
mov al, ch
int 0x10 ; Print the low nibble
pop cx
pop ax
ret
.table: db "0123456789ABCDEF", 0
; Uncomment these lines if not using a BPB (via bpb.inc)
; numHeads: dw 2 ; 1.44MB Floppy has 2 heads & 18 sector per track
; sectorsPerTrack: dw 18
align 2
mouseX: dw 0 ; Current mouse X coordinate
mouseY: dw 0 ; Current mouse Y coordinate
curStatus: db 0 ; Current mouse status
noMouseMsg: db "Error setting up & initializing mouse", 0x0d, 0x0a, 0
delimCommaSpc:db ", ", 0
bootDevice: db 0x00
; Pad boot sector to 510 bytes and add 2 byte boot signature for 512 total bytes
TIMES 510-($-$$) db 0
dw 0xaa55
该代码可以通过以下方式构建到磁盘映像中：
nasm -f bin boot.asm -o boot.bin
# Build 1.44MB disk image
dd if=/dev/zero of=disk.img bs=1024 count=1440
dd if=boot.bin of=disk.img conv=notrunc
I'm supplying this code because I can't tell why your code may have been displaying unwanted pixels occasionally. That kind of issue may be related to the code you didn't provide. When run in VirtualBox it should look something like this:
