3
我一直在试图编写一个基本的com文件的'壳'。 我能够在NASM中组装相同的代码，但几乎没有任何修改。相对跳出范围0020h字节
但是，这个代码不会在TASM汇编！ 我收到这样的错误：相对跳出范围 我在Google上查找了一下，以了解跳转。然而我找不到多少东西，除了打破这个跳跃到相对较短跳跃的想法之外。 有没有更好的选择？
下面的代码：
.model tiny
CR equ 13d
LF equ 10d
TAB equ 09d
.data
prompt db CR,LF,"Input : ",0
tab_max db 7 dup('_'),0
input db 128 dup(0) ; Input Buffer Of 80 Bytes
str_ver db CR,LF,CR,LF,CR," ",\
"Version : 1.0",CR,LF,0
str_help db CR,LF,CR,LF,CR," ",\
"Type VER For Version !!!",\
CR,LF,CR," ",\
"Type CLS To Clear Screen !!!",\
CR,LF,CR," ",\
"Type HELP To Display This Message !!!",\
CR,LF,0
str_welcome db "Welcome To My Operating System !!!",0
str_default db CR,LF,CR,LF,CR," ",\
"Invalid Command !!!",\
CR,LF,CR," ",\
"Type HELP To Display Help !!!",\
CR,LF,0
cmd_ver db "VER",0
cmd_help db "HELP",0
cmd_cls db "CLS",0
.code
org 100h
main proc near
xor ax,ax ; Select Video Mode Function
mov al, 03h ; Select 80x25 (8 Pages) Text Mode
int 10h ; Call Interrupt
mov dh, 0h ; Row
mov dl, 0h ; Column
call goto_xy
mov cx, 30h
lea si, [str_welcome]
call put_str
Begin0:
lea si, [prompt] ; Display Prompt
mov cx, 0ah ; Max Length=10
call put_str
call beep
lea si, [input]
call null_str ; Recycle The Input Buffer
mov cx, 60h ; Max Length=64
call get_str ; Read User Input
call del_whitespace ; Do Away With Leading And Trailing Space Characters
call str_to_upper ; Convert To Uppercase
call chk_internal ; Cross-Check In Internal Commands
jmp Begin0 ; Loop Forever
endp
null_str proc near
push si ; Save SI
push cx ; Save CX
push ax ; Save AX
xor ax, ax
call str_len ; Move Length Of String In CX
.more0:
cmp cx, 0 ; Is It Zero-Length ?
jz .finish0 ; If So Do Away With
mov [si], ax ; Null A Character In Input Buffer
dec cx ; Decrement Counter
inc si ; Advance SI
jmp .more0 ; Loop On Until First 0
.finish0:
pop ax ; Retrieve AX
pop cx ; Retrieve BX
pop si ; Retrieve SI
ret ; Return
endp
del_whitespace proc near
push si ; Save SI
push di ; Save DI
push dx ; Save DX
push cx ; Save CX
push bx ; Save BX
push ax ; Save AX
xor ax, ax
xor bx, bx
xor cx, cx
xor dx, dx
mov di, si
dec si ; SI=SI-1
.loop00:
inc si ; Go On Incrementing Source String Index
xor dx, dx
mov dx, [si]
xor dh, dh
cmp dl, 00h ; Is String Finished ?
jz .chomp00
cmp dl, 20h ; Is It A Space
jz .loop00 ; Go On Eating Spaces
cmp dl, TAB ; Is It A TAB
jz .loop00 ; Go On Eating TABS
push si ; First Non-Whitespace Character Index In String
inc cx ; Number Of Tokens In String
.loop01:
inc si ; Increment SI
mov dx, [si]
xor dh, dh
cmp dx, 00h ; Is String Finished ?
jz .chomp00 ; Cut Out Useful Part
cmp dx, 20h ; Check For Space
jz .loop00
cmp dx, TAB ; Check For TAB
jnz .loop01 ; Read On Until Next TAB
jz .loop00
.chomp00:
cmp cx, 00h ; Null Input
jz .over01 ; Return Then
dec cx ; Otherwise Decrement Number Of Tokens
pop si ; Start Of Finishing Token
mov ax, si ; Save It, Just In Case It Becomes Also The Start Of The First Token
.bypass:
inc si ; Increment String Index
mov dx, [si]
xor dh, dh
cmp dx, 00h ; Has String Ended?
jz .loop002
cmp dx, 20h
jz .loop002
cmp dx, TAB
jnz .bypass ; Bypass All Characters In Token Until First Whitespace
.loop002:
mov bx, si ; Found End
cmp cx, 00h ; Is There Only One Token?
jz .inst00 ; Then Start Of Finishing Token=Start Of Opening Token
.loop02:
dec cx
pop ax ; Move Start Of Previous Token In AX
cmp cx, 00h ; All Tokens Finished?
jz .inst00
jnz .loop02 ; Loop Over
.inst00:
mov si, ax ; Set SI To Start
.loop03:
cmp si, bx ; All Characters In Token Processed ?
jz .over00 ; Done, Return
mov dx, [si]
mov [di], dx ; Otherwise Overwrite Input String
inc si ; Increment User Token Input Index
inc di ; Increment Processed Token Input Index
jmp .loop03 ; Loop Over
.over00:
xor dx, dx
mov [di], dx ; NULL-Terminate Processed Token
.over01:
pop ax ; Retrieve AX
pop bx ; Retrieve BX
pop cx ; Retrieve CX
pop dx ; Retrieve DX
pop di ; Retrieve DI
pop si ; Retrieve SI
ret ; Return
endp
clr_scr proc near
push ax ; Save AX
push bx ; Save BX
push cx ; Save CX
push dx ; Save DX
xor dx, dx ; Cursor At Top-Left
call goto_xy
mov ah, 6 ; Scroll Up Whole Screen
mov al, 0 ; Text Color : White
mov bh, 7 ; Background : Black
xor cx, cx ; Top-left
mov dh, 24 ; Bottom-Most
mov dl, 79 ; Right-Most
int 10h
pop dx ; Retrieve DX
pop cx ; Retrieve CX
pop bx ; Retrieve BX
pop ax ; Retrieve AX
ret
endp
chk_internal proc near
push si ; Save SI
push cx ; Save CX
cmd_ver_lb:
lea di, [cmd_ver] ; VER Command
call cmp_str ; Compare User Input
jnc .do_ver ; Execute Command If Matched
cmd_help_lb:
lea di, [cmd_help] ; HELP Command
call cmp_str ; Compare User Input
jnc .do_help ; Execute Command If Matched
cmd_cls_lb:
lea di, [cmd_cls] ; CLS Command
call cmp_str ; Compare User Input
jnc .do_cls ; Execute Command If Matched
default_lb:
lea si, [str_default] ; Default Error Message
mov cx, 60h ; Max Length 60Hex Characters
call put_str
jmp .clean0 ; Return
.do_ver:
lea si, [str_ver] ; String For VER
mov cx, 40h ; Max Length 40Hex Characters
call put_str
jmp .clean0 ; Return
.do_help:
lea si, [str_help] ; String For HELP
mov cx, 80h ; Max Length 80Hex Characters
call put_str
jmp .clean0 ; Return
.do_cls:
call clr_scr ; Call Clear Screen Function
jmp .clean0 ; Return
.clean0:
pop cx ; Retrieve CX
pop si ; Retrieve SI
ret ; Return
endp
get_xy proc near
push ax ; Save AX
xor ax, ax
mov ah, 03h ; Select Put Cursor Function
int 10h ; Call Interrupt
pop ax ; Retrieve AX
ret
endp
goto_xy proc near
push ax ; Save AX
push bx ; Save BX
push cx ; Save CX
push dx ; Save DX
xor ax, ax
xor cx, cx
mov ah, 02h ; Select Put Cursor Function
mov bh, 00h ; Select Page (0-7)
int 10h ; Call Interrupt
pop dx ; Retrieve DX
pop cx ; Retrieve CX
pop bx ; Retrieve BX
pop ax ; Retrieve AX
ret
endp
cmp_str proc near
push si ; Save SI
push di ; Save DI
push ax ; Save AX
push bx ; Save BX
push cx ; Save CX
clc ; Default : Clear Carry
call str_len ; String Length Of SI
mov ax, cx ; Copy String-Length Of SI In AX
push si ; Save SI
mov bx, di
mov si, bx ; Move DI to SI
call str_len ; String Length Of DI
mov bx, cx ; Copy String-Length Of DI In BX
pop si ; Retrieve Back SI
cmp ax, bx ; Check If String Lengths Are Equal
jnz .nosame ; Not Same
Loop0:
mov al, [si] ; Load Next Character From SI to AL
mov bl, [di] ; Load Next Character From DI to BL
cmp al, bl ; Compare Two Characters
jnz .nosame ; Not Same
or al, al ; Check If AL=0
jz Loop0Done ; AL=0? Then Return
inc si ; Increment SI
inc di ; Increment DI
jmp Loop0
.nosame :
stc ; Set Carry Flag
Loop0Done:
pop cx ; Retrieve CX
pop bx ; Retrieve BX
pop ax ; Retrieve AX
pop di ; Retrieve DI
pop si ; Retrieve SI
ret
endp
put_str proc near
push si ; Save SI
push ax ; Save AX
push cx ; Save CX
Print:
cmp cx, 0h ; Check If CX=0
jz PrintDone ; Don't Bother Printing Further
lodsb ; Load Next Character From SI to AL
or al, al ; Check If AL=0
jz PrintDone ; AL=0? Then Return
call put_chr ; Else Go On To Print Character
dec cx ; Decrement Counter
jmp Print
PrintDone:
pop cx ; Retrieve CX
pop ax ; Retrieve AX
pop si ; Retrieve SI
ret
endp
put_chr proc near
push ax ; Save AX
cmp al, TAB ; Check For Tab Character
jnz no_tab ; Skip Tab Processing
push si
lea si, [tab_max] ; Tab String Of Spaces (7)
push cx
mov cx, 07d
call put_str ; Print Out Tab Characters
pop cx
pop si
jmp key_tab ; Don't Print ASCII 09d (TAB)
no_tab:
mov ah, 0eh ; Select Print Character Function
int 10h ; Print Character
key_tab:
pop ax ; Retrieve AX
ret
endp
get_ch proc near
ReadLoop1:
mov ah, 0 ; Read Key Opcode
int 16h
cmp al, 0 ; ALT, SHIFT, CTRL etc
jz ReadLoop1 ;If so, don't echo this keystroke
;call put_chr
ret
endp
get_chr proc near
ReadLoop2:
mov ah, 0 ; Read Key Opcode
int 16h
cmp al, 0 ; ALT, SHIFT, CTRL etc
jz ReadLoop2 ; If So, Don't Echo This Keystroke
call put_chr ; Echo Character
ret
endp
get_str proc near
push si ; Save SI
push ax ; Save AX
push bx ; Save BX
push cx ; Save CX
mov bx, si ; Copy Initial Address
Count0:
call get_ch
cmp al, 08d
jz .bksp
cmp al, 13d
jz Count0Done
cmp cx, 0h
jz Count0
jmp .next
.bksp:
cmp bx, si ; Is It The First Key ?
jz Count0 ; Go Back Then
push ax ; Save AX
dec si ; Reduce One Character
inc cx ; Free Up Deleted Character
cmp [si], TAB ; Is It A TAB ?
jz .is_tab
push bx
push cx
push dx
xor bx, bx ; Select Video Page 0
call get_xy ; Read Cursor Position In DX
cmp dl, 0h ; Is It The First Column ?
jz .f_col00
mov al, 08h ; Print Backspace
call put_chr
mov al, 20h ; Print Space
call put_chr
mov al, 08h ; Print Backspace
call put_chr
jmp .n_col00
.f_col00:
dec dh ; Go To Previous Line
; Assumes DH>0
mov dl, 79d ; Max Numbers Of Columns
call goto_xy ; Place Cursor
mov al, 20h ; Print Space
call put_chr
mov dl, 79d ; Max Numbers Of Columns
call goto_xy ; Place Cursor
.n_col00:
pop dx
pop cx
pop bx
jmp .not_tab
.is_tab:
push cx
mov cx, 07d
.loop_tab:
push bx
push cx
push dx
xor bx, bx ; Select Video Page 0
call get_xy ; Read Cursor Position In DX
cmp dl, 0h ; Is It The First Column ?
jz .f_col01
mov al, 08h ; Print Backspace
call put_chr
mov al, 20h ; Print Space
call put_chr
mov al, 08h ; Print Backspace
call put_chr
jmp .n_col01
.f_col01:
dec dh ; Go To Previous Line
; Assumes DH>0
mov dl, 79d ; Max Numbers Of Columns
call goto_xy ; Place Cursor
mov al, 20h ; Print Space
call put_chr
mov dl, 79d ; Max Numbers Of Columns
call goto_xy ; Place Cursor
.n_col01:
pop dx
pop cx
pop bx
dec cx
cmp cx, 0
jnz .loop_tab
pop cx
.not_tab:
xor ax, ax
mov [si], ax ; Reset Deleted Character To 0
pop ax
jmp Count0
.next:
cmp cx, 0h ; Is Buffer Already Full ?
jz Count0 ; Go Back And Wait For BKSP or ENTER
dec cx ; Decrement Max String Length
call put_chr
mov [si], al
inc si ; Increment SI
jmp Count0
Count0Done:
pop cx ; Retrieve CX
pop bx ; Retrieve BX
pop ax ; Retrieve AX
pop si ; Retrieve SI
ret
endp
str_len proc near
push ax ; Save AX
push si ; Save SI
xor cx, cx ; Initialize Counter
Count:
lodsb ; Load Next Character From SI to AL
or al, al ; Check If AL=0
jz CountDone ; AL=0? Then Return
inc cx
jmp Count
CountDone:
pop si ; Retrieve SI
pop ax ; Retrieve AX
ret
endp
chr_to_upper proc near
push bx ; Save BX
push cx ; Save CX
push ax ; Save AX
mov bl, al
mov al, 'a'
cmp bl, al ; Is Character < 'a'
jl .notlc ; Other
mov al, 'z'
cmp bl, al ; Is Character > 'z'
jg .notlc ; Other
mov al, 20h
sub bl, al ; Convert to Uppercase
xchg al, bl ; Exchange AL and BL
jmp .lc ; Lowercase Processed
.notlc:
pop ax ; Retrieve AX
jmp .clear1
.lc:
pop cx ; Waste AX
.clear1:
pop cx ; Retrieve CX
pop bx ; Retrieve BX
ret
endp
chr_to_lower proc near
push bx ; Save BX
push cx ; Save CX
push ax ; Save AX
mov bl, al
mov al, 'A'
cmp bl, al ; Is Character < 'A'
jl .notuc ; Other
mov al, 'Z'
cmp bl, al ; Is Character > 'Z'
jg .notuc ; Other
mov al, 20h
add bl, al ; Convert to Lowercase
xchg al, bl ; Exchange AL and BL
jmp .uc ; Uppercase Processed
.notuc:
pop ax ; Retrieve AX
jmp .clear2
.uc:
pop cx ; Waste AX
.clear2:
pop cx ; Retrieve CX
pop bx ; Retrieve BX
ret
endp
str_to_upper proc near
push si ; Save SI
push ax ; Save AX
Count1:
mov al, [si]
cmp al, 0h ; Check If AL=0
jz Count1Done ; AL=0? Then Return
mov al, 'a'
cmp [si], al ; Is Character < 'a'
jl .Other1 ; Other
mov al, 'z'
cmp [si], al ; Is Character > 'z'
jg .Other1 ; Other
mov al, 20h
sub [si], al ; Convert to Uppercase
.Other1:
inc si ; Increment SI
jmp Count1
Count1Done:
pop ax ; Retrieve AX
pop si ; Retrieve SI
ret
endp
str_to_lower proc near
push si ; Save SI
push ax ; Save AX
Count2:
mov al, [si]
or al, al ; Check If AL=0
jz Count2Done ; AL=0? Then Return
mov al, 'A'
cmp [si], al ; Is Character < 'A'
jl .Other2 ; Other
mov al, 'Z'
cmp [si], al ; Is Character > 'Z'
jg .Other2 ; Other
mov al, 20h
add [si], al ; Convert to Lowercase
.Other2:
inc si ; Increment SI
jmp Count2
Count2Done:
pop ax ; Retrieve AX
pop si ; Retrieve SI
ret
endp
sound proc near
push ax
push cx
mov cx, ax ; Temporarily Save Note Value
mov al, 182
out 43h, al
mov ax, cx ; Set up frequency
out 42h, al
mov al, ah
out 42h, al
in al, 61h ; Switch PC speaker on
or al, 03h
out 61h, al
pop cx
pop ax
ret
endp
delay proc near
os_pause:
push ax
cmp ax, 0
je .time_up ; If delay = 0 then bail out
mov cx, 0
mov [.counter_var], cx ; Zero the counter variable
mov bx, ax
mov ax, 0
mov al, 1 ; 1 * 55ms = 55mS
mul bx ; Multiply by number of 55ms chunks required
mov [.orig_req_delay], ax ; Save it
mov ah, 0
int 1Ah ; Get tick count
mov [.prev_tick_count], dx ; Save it for later comparison
.checkloop:
mov ah,0
int 1Ah ; Get tick count again
cmp [.prev_tick_count], dx ; Compare with previous tick count
jne .up_date ; If it's changed check it
jmp .checkloop ; Otherwise wait some more
.time_up:
pop ax
ret
.up_date:
mov ax, [.counter_var] ; Inc counter_var
inc ax
mov [.counter_var], ax
cmp ax, [.orig_req_delay] ; Is counter_var = required delay?
jge .time_up ; Yes, so bail out
mov [.prev_tick_count], dx ; No, so update .prev_tick_count
jmp .checkloop ; And go wait some more
.orig_req_delay dw 0
.counter_var dw 0
.prev_tick_count dw 0
endp
mute proc near
push ax
in al, 61h
and al, 0FCh
out 61h, al
pop ax
ret
endp
beep proc near
push ax
mov ax, 560d ; Sound Tone
call sound
xor ax, ax
mov ax, 02h ; 110 milliseconds
call delay
call mute
pop ax
ret
endp
end main
它会在_NASM_中工作（即使使用位16指令），因为_NASM_会将该分支编码为2字节的_WORD_位移。虽然它会默默编码，但它可能无法按预期在386以上的处理器上正常运行。仿真8086/80186/80286的处理器/仿真器可能存在问题。如果您在分支指令的标签名称之前放置了关键字_SHORT_，则在_NASM_中会出现警告/错误。这会迫使_NASM_使用8位位移，从而导致您使用_TASM_看到的类似问题。 –