jb count_others cmp al,'Z' jb count_letter cmp al,'a' jb count_others jmp count_letter
count_letter: inc bx jmp repeat
count_digit: inc cx jmp repeat
count_others: inc dx jmp repeat
exit: push cx push dx call print_crlf lea dx,letter mov ah,9 int 21h mov ax,bx call print_ax call print_crlf lea dx,others mov ah,9 int 21h pop dx ;栈，后进先出，先进后出 mov ax,dx call print_ax call print_crlf lea dx,digit mov ah,9 int 21h pop cx ;print_ax会修改cx的值,故要先把cx进栈 mov ax,cx call print_ax
jmp exit2
print_crlf proc near lea dx,crlf mov ah,9 int 21h ret
print_crlf endp
print_ax proc near
mov cl,10 mov si,0
repeat2: div cl
mov dl,ah add dl,30h
mov dh,0 push dx inc si mov ah,0
cmp al,0 jnz repeat2
l3: pop dx mov ah,2 int 21h dec si cmp si,0 jnz l3
ret print_ax endp
exit2: mov ah,4ch int 21H
main endp s3 ends
end main
17.已定义两个整数变量A和B，试编写程序完成以下功能
（1）若两个树种有一个是奇数，则将奇数存入A中，偶数存入B中 （2）若两个数均为奇数，则将两个数加1后存回原变量 （3）若两个数均为偶数，则两个变量均不变
s1 segment stack
dw 100h dup(?) top label word s1 ends
s2 segment a dw 12,'$' b dw -13,'$' s2 ends
s3 segment
assume cs:s3,ds:s2,ss:s3 main proc far mov ax,s1 mov ss,ax lea sp,top mov ax,s2 mov ds,ax mov si,0 mov di,0 mov dx,0 mov cx,2 mov ax,a[0] cmp ax,0 jnl next neg ax
next:div cx cmp dx,1 jnz l mov si,1
l: mov dx,0 mov ax,b[0] cmp ax,0 jnl next2
neg ax
next2: div cx cmp dx,1 jnz l2 mov di,1
l2: cmp si,0 jnz l3 cmp di,0 jnz l4 jmp exit ;都是偶数，跳转到末尾
l3: cmp di,0 jnz l5 jmp exit ;a[0]为奇数，b[0]为偶数，跳转到末尾
l5: mov ax,a[0] ;a[0]，b[0]为奇数，a[0]加一存回原变量 cmp ax,0 jnl l6 neg ax dec ax neg ax jmp l7 l6: inc ax l7: mov a[0],ax mov ax,b[0] ;a[0]，b[0]为奇数，b[0]加一存回原变量 cmp ax,0 jnl l8 neg ax dec ax neg ax jmp l9 l8: inc ax l9: mov b[0],ax jmp exit
l4: mov ax,a[0] ;a[0]为偶数，b[0]为奇数，互换 mov bx,b[0] mov a[0],bx mov b[0],ax
exit: mov ah,4ch
int 21H
main endp s3 ends
end main
18.写一段子程序skiplines，完成输出空行的功能。空行的行数由用户在主程序中通过键盘输入，并将行数放在ax寄存器中
s1 segment stack
dw 100h dup(?) top label word s1 ends
s2 segment
crlf db 0dh,0ah,24h,'$' s2 ends
s3 segment
assume cs:s3,ds:s2,ss:s3 main proc far mov ax,s1 mov ss,ax lea sp,top mov ax,s2 mov ds,ax mov bx,0
l: mov ah,1 int 21h cmp al,0dh jz next cbw
sub ax,30h xchg ax,bx mov cx,10 mul cx xchg ax,bx add bx,ax
jmp l
next:mov ax,bx call skiplines