当我尝试在x86汇编中为 Boot 加载程序编写一些例程时，我遇到了一个bug，当除法错误发生时，程序会陷入无限循环。通过调查，我发现调用int 0会正常地通过异常处理程序，然后继续执行程序的其余部分。为x86编写自己的异常处理程序时，除法错误异常发生时的返回地址是指令的地址，这意味着它只会一遍又一遍地循环执行除法。2这是正常行为还是Virtualbox/my cpu特有的bug？

org 0x7c00      ;put all label addresses at offset 0x7c00

xor ax, ax      ;set up all segment registers
mov ds, ax
mov ax, 0x9000
mov ss, ax
mov sp, 0x1000
mov ax, 0xB800  ;video text memory starts at this address
mov es, ax

mov ah, 0x00
mov al, 0x02
int 0x10        ;go into 80x25 monochrome text

mov [0x0000], word DivideException
mov [0x0002], word 0x0000

xor di, di
xor bx, bx

;int 0   ;this and the divide CX below will cause a division error exception

mov ax, 0
mov cx, 0 ;when exception is handled it prints out
div cx    ;"a divide by zero error happened 0000:7C2D 0000:7C2F
          ;the first address is the division instruction and the second one is 2 bytes after
          ;when int 0 is uncommented out then it will have the two same addresses
jmp $

ToHex:
push bp
mov bp, sp
push bx

mov ax, word [bp+6]
mov bx, word [bp+4]
add bx, 3
mov cx, 16

.Loop:
xor dx, dx
div cx
add dx, 48
cmp dx, 58
jb .Skip
add dx, 7
.Skip:
mov byte [bx], dl
dec bx
cmp ax, 0
jne .Loop

.Ret:
pop bx
mov sp, bp
pop bp
ret

PrintStr:
push bp
mov bp, sp
push bx

mov bx, word [bp+6]
mov ah, byte [bx]
mov bx, word [bp+4]

.PrintLoop:
mov al, byte [bx]

mov word [es:di], ax
inc di
inc di
inc bx
cmp byte [bx], 0x00
jne .PrintLoop

pop bx
mov sp, bp
pop bp
ret

DivideException:
push bp
mov bp, sp
push bx

push word ColorAttributes1
push word String3
call PrintStr
add sp, 4

push word [bp+4]
push word String1
call ToHex
add sp, 4

push word [bp+2]
push word String2
call ToHex
add sp, 4

push word ColorAttributes1
push word String1
call PrintStr

push ds
mov ds, word [bp+4]
mov bx, word [bp+2]

cmp byte [ds:bx], 0xF7  ;checks if theres a 0xF7 byte at the return address
jne .DontAdd            ;for some reason the return address when calling int 0
add word [bp+2], 2      ;directly is the address after the instruction while
.DontAdd:               ;causing a divide error exception through divsion will
pop ds                  ;put the return address at the division leading to an
                        ;infinite loop
push word [bp+4]
push word String1
call ToHex
add sp, 4

push word [bp+2]
push word String2
call ToHex
add sp, 4

push word ColorAttributes1
push word String1
call PrintStr

add sp, 4

pop bx
mov sp, bp
pop bp
iret


String1: db "0000:";, 0x00
String2: db "0000 ", 0x00
String3: db "a divide by zero error happened ", 0x00
ColorAttributes1: db 0x0F ; first nibble is backround color
                         ;second nibble is foreground

times 2048-2- ($-$$) db 0  ;fills the rest with 0's until 510 bytes
dw 0xAA55               ;magic boot sector number