[org 0x7c00]
xor ax, ax
mov ds, ax
mov es, ax
mov ss, ax
mov sp, 0x7C00
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
mov SI, bm1
call printf
mov SI, bm2
call printf
call cls
mov bh, 70h
call color
mov SI, welmsg
call printf
wywtd:
mov SI, welmsg2
call printf
call waitforkey
cmp al, 49
je reboot
cmp al, 50
je guess
mov SI, invalidmsg
call printf
call waitforkey
call cls
mov bh, 70h
call color
JMP wywtd
jmp $
good:
mov SI, okans
call printf
call waitforkey
call reboot
guess:
call cls
mov bh, 70h
call color
mov SI, gmsg
call printf
call waitforkey
cmp al, 49
je good
mov SI, wrongans
call printf
call waitforkey
reboot:
db 0x0ea
dw 0x0000
dw 0xffff
color:
mov ah, 06h
xor al, al
xor cx, cx
mov dx, 184FH
; mov bh, 1Fh
int 10h
ret
waitforkey:
mov ah, 00h
int 16h
ret
cls:
pusha
mov ah, 0x00
mov al, 0x03
int 0x10
popa
ret
newline:
mov SI, nl
printf:
mov ah, 0x0e
mov bx, 000Fh ; DisplayPage BH=0, GraphicsColor BL=15 (BrightWhiteOnBlack)
.Loop:
mov al, [SI]
test al, al
jz .Exit
int 0x10
inc SI
jmp .Loop
.Exit:
ret
okans: db "Correct answer!", 0x00
wrongans: db "Wrong answer!", 0x00
gmsg: db "What is 78 * 23?", 0x0a, 0x0d, "[1] 1794", 0x0a, 0x0d, "[2] 1894", 0x0a, 0x0d, "[3] 1872", 0x0a, 0x0d, 0x00
invalidmsg: db "Invalid option!", 0x0a, 0x0d, 0x00
nl: db 0x0a, 0x0d, 0x00
welmsg: db "Welcome to ZahonOS Light edition!", 0x0a, 0x0d, 0x00
welmsg2: db "what do you want to do?", 0x0a, 0x0d, "[1] Restart", 0x0a, 0x0d, "[2] Game", 0x0a, 0x0d, 0x0a, 0x0d, "Answer: ", 0x00
bm1: db "Booting ZahonOS Light edition...", 0x0a, 0x0d, 0x00
bm2: db "Done!", 0x00
times 510-($-$) db 0
dw 0xaa55
When a bootsector program begins, the segment registers cannot be trusted to contain any particular value. In accordance with your [org 0x7c00] and the instructions that you further use to address memory, the DS segment register needs to contain 0. You must set it up yourself:
xor ax, ax
mov ds, ax
mov es, ax
Similarly, your program accesses the stack a lot but you don't make sure that the pre-existing stack is up to that task. You must set it up yourself:
xor ax, ax
mov ss, ax
mov sp, 0x7C00 ; Right below the bootsector
The BIOS.Teletype function 0Eh already uses the BL and BH registers (together they form BX) as some of its parameters. Therefore it would be better to use the SI register as the pointer that you provide to your printf.
At the conclusion of processing an invalid answer you use call wywtd to repeat all over again. It makes more sense to not call but rather jump in this instance:
jmp wywtd
I don't know if this is on purpose, but the bm1 and bm2 messages are immediately erased by you clearing the screen...
call reboot
reboot:
This call reboot is redundant. The execution can just as well fall through into reboot:.
newline:
mov SI, nl
call printf
ret
You could replace this so-called tail call by a jump jmp printf. But the most efficient would be to put the newline code directly above the printf code. That would shave off even the jmp printf:
newline:
mov SI, nl
printf:
...
[org 0x7c00]
xor ax, ax
mov ds, ax
mov es, ax
mov ss, ax
mov sp, 0x7C00
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
call newline
mov SI, bm1
call printf
mov SI, bm2
call printf
call cls
mov bh, 70h
call color
mov SI, welmsg
call printf
wywtd:
mov SI, welmsg2
call printf
call waitforkey
cmp al, 49
je reboot
cmp al, 50
je guess
mov SI, invalidmsg
call printf
call waitforkey
call cls
mov bh, 70h
call color
JMP wywtd
jmp $
good:
mov SI, okans
call printf
call waitforkey
call reboot
guess:
call cls
mov bh, 70h
call color
mov SI, gmsg
call printf
call waitforkey
cmp al, 49
je good
mov SI, wrongans
call printf
call waitforkey
reboot:
db 0x0ea
dw 0x0000
dw 0xffff
color:
mov ah, 06h
xor al, al
xor cx, cx
mov dx, 184FH
; mov bh, 1Fh
int 10h
ret
waitforkey:
mov ah, 00h
int 16h
ret
cls:
pusha
mov ah, 0x00
mov al, 0x03
int 0x10
popa
ret
newline:
mov SI, nl
printf:
mov ah, 0x0e
mov bx, 000Fh ; DisplayPage BH=0, GraphicsColor BL=15 (BrightWhiteOnBlack)
.Loop:
mov al, [SI]
test al, al
jz .Exit
int 0x10
inc SI
jmp .Loop
.Exit:
ret
okans: db "Correct answer!", 0x00
wrongans: db "Wrong answer!", 0x00
gmsg: db "What is 78 * 23?", 0x0a, 0x0d, "[1] 1794", 0x0a, 0x0d, "[2] 1894", 0x0a, 0x0d, "[3] 1872", 0x0a, 0x0d, 0x00
invalidmsg: db "Invalid option!", 0x0a, 0x0d, 0x00
nl: db 0x0a, 0x0d, 0x00
welmsg: db "Welcome to ZahonOS Light edition!", 0x0a, 0x0d, 0x00
welmsg2: db "what do you want to do?", 0x0a, 0x0d, "[1] Restart", 0x0a, 0x0d, "[2] Game", 0x0a, 0x0d, 0x0a, 0x0d, "Answer: ", 0x00
bm1: db "Booting ZahonOS Light edition...", 0x0a, 0x0d, 0x00
bm2: db "Done!", 0x00
times 510-($-$) db 0
dw 0xaa55
发布评论
评论（1）
当引导扇区程序开始时，不能相信段寄存器包含任何特定值。根据您的
[org 0x7c00]以及您进一步用于寻址内存的指令，DS段寄存器需要包含0。您必须自己设置它：类似，您的程序经常访问堆栈，但您不确定预先存在的堆栈是否能够胜任该任务。您必须自己进行设置：
BIOS.Teletype 函数 0Eh 已使用
BL和BH寄存器（它们一起形成BX）作为它的参数。因此，最好使用SI寄存器作为提供给 printf 的指针。处理无效答案后，您可以使用
call wywtd再次重复。在这种情况下，不调用而是跳转更有意义：我不知道这是否是故意的，但是bm1和bm2 消息会在您清除屏幕后立即删除...
这个
调用reboot是多余的。执行也可以进入重新启动：。您可以用跳转
jmp printf来替换这个所谓的尾调用。但最有效的方法是将 newline 代码直接放在 printf 代码之上。这甚至会减少
jmp printf：When a bootsector program begins, the segment registers cannot be trusted to contain any particular value. In accordance with your
[org 0x7c00]and the instructions that you further use to address memory, theDSsegment register needs to contain 0. You must set it up yourself:Similarly, your program accesses the stack a lot but you don't make sure that the pre-existing stack is up to that task. You must set it up yourself:
The BIOS.Teletype function 0Eh already uses the
BLandBHregisters (together they formBX) as some of its parameters. Therefore it would be better to use theSIregister as the pointer that you provide to your printf.At the conclusion of processing an invalid answer you use
call wywtdto repeat all over again. It makes more sense to not call but rather jump in this instance:I don't know if this is on purpose, but the bm1 and bm2 messages are immediately erased by you clearing the screen...
This
call rebootis redundant. The execution can just as well fall through into reboot:.You could replace this so-called tail call by a jump
jmp printf.But the most efficient would be to put the newline code directly above the printf code. That would shave off even the
jmp printf: