1 data segment 2 str_source db "Hello ** World ** 09aAzZ$" 3 str1 db 20 dup(0) ;大写字母 4 str2 db 20 dup(0) ;小写字母 5 int_caption dw 0 ;大写字母个数 6 int_lower dw 0 ;小写字母个数 7 data ends 8 9 code segment ;设置代码段s 10 assume cs:code,ds:data 11 12 main proc near 13 start: 14 mov ax , data ;初始化ds 15 mov ds , ax 16 mov si , offset str_source ;offset str_source-->si 变址 17 xor ax , ax 18 push ax ;利用堆栈存储str1,str2当前指针 19 push ax ;str1,str2指针入栈 20 21 read_loop: 22 mov al , [si] ;取[si]中的内容，即偏移量 23 cmp al , '$' 24 je exit 25 26 cmp al , 'A' 27 jb loop_next ;< 28 cmp al , 'z' 29 ja loop_next ;> 30 cmp al , 'a' 31 jnl lower_case ;>= 32 cmp al , 'Z' 33 ja loop_next ;> 34 35 pop di ;大写 36 mov str1[di] , al 37 inc di 38 push di 39 inc int_caption 40 jmp loop_next 41 lower_case: ;小写 42 pop bx ;str1指针暂存 43 pop di 44 mov str2[di] , al 45 inc di 46 push di 47 push bx 48 inc int_lower 49 loop_next: 50 inc si 51 jmp read_loop 52 53 exit: 54 pop di ;将str1指针弹栈，切勿在子程序中弹栈-->子程序中为新栈 55 call print_caption 56 57 call print_crlf 58 59 pop di 60 call print_lowercase 61 62 mov ax , 4c00h ;返回DOS 63 int 21h 64 main endp 65 66 print_ax_dec proc near 67 or ax , ax 68 jz zero 69 mov bx , -1 ;余数栈底标志 70 push bx 71 mov bx , 10 ;除数 72 73 repeat: xor dx , dx 74 div bx 75 mov cx , ax ;商 76 or cx , dx 77 jz print_exit ;商与余数全零则结束 78 push dx 79 jmp repeat 80 81 zero: mov dl , 30h 82 mov ah , 02h 83 int 21h 84 85 print_exit: 86 pop dx 87 cmp dx , -1 88 je proc_exit 89 add dx , 30h 90 mov ah , 02h 91 int 21h 92 jmp print_exit 93 94 proc_exit: 95 ret 96 print_ax_dec endp 97 print_caption proc near 98 mov al , '$' 99 mov str1[di],al 100 mov dx , offset str1 ;一定要为dx,偏移地址 101 mov ah , 09h 102 int 21h 103 104 call print_space 105 mov ax , int_caption 106 call print_ax_dec 107 ret 108 print_caption endp 109 print_lowercase proc near 110 mov al , '$' 111 mov str2[di],al 112 mov dx , offset str2 ;一定要为dx,偏移地址为16位 113 mov ah , 09h 114 int 21h 115 116 call print_space 117 mov ax , int_lower 118 call print_ax_dec 119 ret 120 print_lowercase endp 121 print_space proc near 122 mov dl , 20h ;空格 123 mov ah , 02h 124 int 21h 125 ret 126 print_space endp 127 print_crlf proc near 128 mov dl , 0ah ;回车换行 129 mov ah , 02h 130 int 21h 131 mov dl , 0dh 132 mov ah , 02h 133 int 21h 134 ret 135 print_crlf endp 136 137 code ends ;代码段结束 138 end start ;汇编语言源程序结束