由于软盘是开发操作系统的最简单的存储介质,我购买了3.5英寸软盘驱动器.

我使用NASM作为汇编编译器,qemu作为模拟器.
使用dd命令,我将一个现有的和空的(就文件而言)软盘克隆到一个名为floppy.img.bak的文件中.

之后,我在x86程序集中编写了一个简单的bootloader：

bootloader.asm

org 7C00h
jmp 0x0000:start    ;go 
 
msg db 'Loading Kernel...',0
 
start:
    ;update the segment registers
    mov ax,cs
    mov ds,ax
    mov es,ax
 
    mov si,msg
 
print:          ;prints a string
    lodsb       ;load next char
 
    cmp al,0   ;if null terminator...
    je reset    ;...jump to reset:
 
    mov ah,0Eh ;print AL
    mov bx,7   
    int 10h
 
    jmp print   ;if not null terminator,continue printing
 
reset:          ;resets the floppy drive
    mov ax,0   ;
    mov dl,0   ;drive=0 (=A)
    int 13h     ;
    jc reset    ;if error resetting,reset again
 
read:
    mov ax,1000h ;ES:BX = 1000:000
    mov es,ax  ;es is 1000h now
    mov bx,0   ;bx is 0 now
 
    mov ah,2   ;load disk data into ES:BX
    mov al,1   ;load 1 sector
    mov ch,0   ;cylinder=0
    mov cl,2   ;sector=2
    mov dh,0   ;head=0
    mov dl,0   ;drive=0
    int 13h     ;read!
 
    jc read     ;if error then try again
 
 
    jmp 1000h:0000;jump to the program
 
times 510-($-$$) db 0
dw 0AA55h

到现在为止还挺好.
我的简单临时存根内核如下：

kernel.asm

kstart:
    mov ah,9
    mov al,'k'
    mov bx,7
    mov cx,5
    int 10h
 
hang:
    jmp hang
 
times 510-($-$$)+2 db 0

我还有一个shell脚本来编译,编写和启动这个设置：

compile-and-run.sh

cd ~/Dev/OS                                                          # cd to here
 
rm asm-bin/bootloader.bin                                               # remove old compiled bootloader
rm asm-bin/kernel.bin                                                   # remove old compiled kernel
 
nasm asm-src/bootloader.asm -f bin -o asm-bin/bootloader.bin            # compile bootloader
nasm asm-src/kernel.asm -f bin -o asm-bin/kernel.bin                    # compile kernel
 
rm images/floppy.img                                                    # remove old floppy image
cp images/floppy.img.bak images/floppy.img                              # copy original floppy image to fresh one
 
dd if=asm-bin/bootloader.bin of=images/floppy.img bs=512 count=1 seek=0 # write bootloader to first sector
dd if=asm-bin/kernel.bin of=images/floppy.img bs=512 count=1 seek=1     # write kernel to second sector
 
qemu-system-i386 images/floppy.img                                      # start qemu and boot floppy.img

现在,qemu的预期输出将是(至少我理解的)：

Loading Kernel...
kkkkk

但相反,它是：

Loading Kernel...

所以,显然,跳跃有些不对劲,我只是不知道是什么.
也许你可以帮助我？我会很感激.