如何将每个句子的第一个字母转换为大写和所有其他字母转换为小写（Assembly）？

Question

下面是一个使每个句子的第一个字母大写的程序。但是，我需要修改该程序，以便使其他字母小写。另外，可能会有很多句子。到目前为止，我已经注意到该程序在我的电脑上运行得并不顺利，但这可能不是我程序的错。无论如何，我很难弄清楚如何正确修改这个程序以适应需求。提前感谢您！

.model small 
    .stack 100h 
    .data 

BUFSIZE EQU 4096 ; constant - the size of the buffer 
input db 'data.txt',0 ; default input file 
output db 'result.txt',0 ; default output file 
msg1 db 'Choose data file [data.txt]: $' 
msg2 db 10,13,'Choose result file [rezult.txt]: $' 
msg3 db 10,13,'Error, the file could not be found, working with default file: data.txt $' 
string1 db 11 dup (?) ; the name of input file 
string2 db 11 dup (?) ; the name of result file 
handle1 dw ? ; file handles 
handle2 dw ? 
buffer db BUFSIZE dup (' ') ; buffer 
.code 
     mov ax, @data ; loading data segment 
     mov ds,ax 
     sub cx,cx 
     mov si, 80h 
     mov cl,es:[si] 
     cmp cx, 0 
     mov bx,0  
     je label1 
     inc si 
     inc si 
     dec cx 

read: mov al,es:[si] 
     cmp al,' '  
     je second 
     mov string1[bx],al 
     inc si 
     inc bx 
     loop read 

second: 
     mov string1[bx],0 

     mov bx,0 
     dec cx 

looper: inc si 
      mov al,es:[si] 
      mov string2[bx],al 
      inc bx 
      loop looper 

      mov string2[bx],0 
      mov bx,100h 
      push bx 
      jmp open  

label1: mov ah, 9 
      mov dx, offset msg1 
      int 21h 

named:  mov ah, 1h 
      int 21h 
      cmp al, 13 
      je eof1 
      mov string1[bx],al 
      inc bx 
      jmp named 

eof1:  mov string1[bx],00h 

open:  mov ah, 3dh 
      mov al, 2 
      mov dx, offset string1 
      int 21h 
      mov handle1, ax 
      mov ah, 59h 
      int 21h 
      cmp al, 2 
      je deflt 
      jmp cont 

deflt:  mov ah,9 
      mov dx,offset msg3 
      int 21h 
      mov ah, 3dh 
      mov al, 2 
      mov dx,offset input 
      int 21h 
      mov handle1,ax 

cont:  pop bx 
      cmp bx,100h 
      je creat2 
      mov ah, 9 
      mov dx, offset msg2 
      int 21h 

      mov bx,0000h 

label2: mov ah, 1h 
      int 21h 
      cmp al, 13 
      je eof2 
      mov string2[bx],al 
      inc bx 
      jmp label2 

eof2:  mov string2[bx],0 
      cmp bx, 0 
      je creat1 
      jmp creat2 

creat1: mov ah, 3ch 
      mov cx, 0 
      mov dx, offset output 
      int 21h 
      mov handle2, ax 
      mov ah, 3eh 
      mov bx, handle2 
      int 21h 
      mov ah, 3dh 
      mov al, 2 
      mov dx, offset output 
      int 21h 
      mov handle2, ax 
      jmp read_s 

creat2: mov ah, 3ch 
      mov cx, 0 
      mov dx, offset string2 
      int 21h 
      mov handle2, ax 
      mov ah, 3eh 
      mov bx, handle2 
      int 21h 
      mov ah, 3dh 
      mov al, 2 
      mov dx, offset string2 
      int 21h 
      mov handle2, ax 

doin: 

read_s: mov ah, 3fh 
      mov bx, handle1 
      mov cx, BUFSIZE 
      mov dx, offset buffer 
      int 21h 
      cmp ax, 0 
      je theend 
      mov bx,ax 

      cmp buffer[0], 'z' 
      ja searching 
      cmp buffer[0], 'a' 
      jb searching 
      sub buffer[0], 32 
      dec bx 
cc: 

edit:  cmp buffer[bx], '?' 
      je higher 
      cmp buffer[bx], '!' 
      je higher 
      cmp buffer[bx], '.' 
      je higher 
      jmp searching 

higher: cmp buffer[bx+1], 'a' 
      jae lower 
      jmp searching 

lower: cmp buffer[bx+1], 'z' 
      jbe changing; 
      jmp searching  

changing: sub buffer[bx+1], 32 

searching: dec bx ; 
      jnz cc 

      mov cx, ax 
      mov ah, 40h 
      mov bx, handle2 
      mov dx, offset buffer 
      int 21h 
      jmp doin 


theend: mov ah, 3eh 
      int 21h 
      mov bx, handle1 
      int 21h 

      mov ah, 4ch  
      int 21h 
end 

Answer 1

嗯，有两种情况下，你必须确保该字符是一个资本 - 在字符串中的第一个字符和后面的任何字符一个“”。其他字符应该是小写字母。

如果字符在[a..z]范围内，将一个函数加入'A' - 'a'（32）开始，将其称为toupper.Now重复此函数并将其更改为使其减去'A'-'a'（32 ）如果属于范围[A..Z]，则由字符组成。

现在只需遍历字符串，加载每个字符。如果它是空终止符，那么你就完成了。如果它是第一个字符，则将其大写，然后保存为最后一个字符，加载另一个字符并再次尝试。如果它不是null并且不是第一个字符，请检查最后一个字符是否为空格。如果是，则将char大写，将其保存为最后一个，然后返回以加载下一个字符。但是，如果最后一个字符不是空格，请使char小写，将其保存为最后一个字符，然后返回以加载下一个字符。

您可以将lastChar变量初始化为0，以确定当前字符是否是字符串中的第一个字符。 此外，还有一些注释和一些更有意义的标签名称会使您的代码在以后的日期更容易回来，或者更容易阅读。 ;） 它是一种值得进入的习惯。

这是一个很好的例子。输出为This Is My Message

;========================================== 
; nasm toupper.asm -f bin -o toupper.com 
;========================================== 
[BITS 16] 
[ORG 0x100]  ; DOS .com program, no header, CS=DS 
EntryPoint: 
    mov  ax, 0x03    ; set text mode 3 - we should already be in this mode, done to clear the screen 
    int  0x10 

    push word myMessage 
    call makePrettyCase 

    push word myMessage 
    call printString 

    int  0x20     ; exit back to dos 

;void printString(*str) 
printString: 
    push bp 
    mov  bp, sp 
    add  bp, 4 
    mov  si, [bp+0]    ; ds:si ---> string 
.getChar: 
    lodsb 
    test al, 0xff    ; sets the flags as if we did 'and al, 0xff' - if the zero flag is set, there are no bits set in al, i.e it's 0 
    jz  .printStringDone 
    mov  ah, 0xe 
    int  0x10 
    jmp  .getChar 
.printStringDone: 
    pop  bp 
    ret  2 

; input: 
;  AL = char 
; outpt: 
;  if al if an alpha char, ensures it is in range A-Z 
toupper: 
    cmp  al, 'a' 
    jb  .toupperDone 
    cmp  al, 'z' 
    ja  .toupperDone 
    add  al, 'A' - 'a'  
.toupperDone: 
    ret 

; input: 
;  AL = char 
; outpt: 
;  if al if an alpha char, ensures it is in range a-z 
tolower: 
    cmp  al, 'A' 
    jb  .tolowerDone 
    cmp  al, 'Z' 
    ja  .tolowerDone 
    sub  al, 'A' - 'a'  
.tolowerDone: 
    ret 

; void makePrettyCase(char *string) 
makePrettyCase: 
    push bp 
    mov  bp, sp 
    add  bp, 4       ; add 2 for the bp we just saved, and 2 for the return address. bp now points at out input var, a pointer to the string 
    pusha 
    mov  si, [bp+0]      ; point source index to string 
    mov  di, si       ; point dest index to string 
    xor  dl, dl       ; DL = lastChar, holds 0 for the first char in the string 
    mov  dh, ' '       ; DH = spaceChar (' ') - holds the ascii code for a space 
.getNextChar: 
    lodsb         ; ds:[si] --> al, si = si+1 
    test al, 0xff 
    jz  .makePrettyCaseDone 
.checkIfFirstInString:      ; if so, capitalize 
; cmp  byte [lastChar], 0 
    cmp  dl, 0 
    jne  .checkIfLastWasSpace 
    jmp  .makeUpper 
.checkIfLastWasSpace:      ; if so, capitalize 
    ;cmp  byte [lastChar], spaceChar 
    cmp  dl, dh 
    jne  .makeLower 
.makeUpper: 
    call toupper 
    stosb         ; al --> es:[di], di = di+1 
    mov  dl, al       ; save this char as our lastChar 
    ;mov  byte [lastChar], al 
    jmp  .getNextChar 
.makeLower: 
    call tolower 
    stosb         ; al --> es:[di], di = di+1 
    mov  dl, al       ; save this char as our lastChar 
    ;mov  byte [lastChar], al 
    jmp  .getNextChar 
.makePrettyCaseDone: 
    popa 
    pop  bp 
    ret  2        ; return and remove the 2 bytes of the input var from the stack 

;========================================== 
[section .data] 
myMessage  db  "THIS IS MY MESSAGE",0