用汇编语言写一个四位秒表

好的，以下是用汇编语言写的四位秒表程序：

; 4-Digit Stopwatch Program

.MODEL SMALL
.STACK 100H

.DATA
    COUNT DB 0        ; Counter for seconds
    DISP  DB 0,0,0,0  ; Display buffer for 4 digits

.CODE
    MAIN PROC
        MOV AX, @DATA   ; Initialize DS register
        MOV DS, AX

        MOV AH, 0        ; Clear screen
        INT 10H

        MOV AH, 2        ; Set cursor position to row 1, column 1
        MOV BH, 0        ; Display page 0
        MOV DH, 0
        MOV DL, 0
        INT 10H

        MOV AH, 1        ; Enable keyboard input
        INT 16H

    START:              ; Main loop
        CALL COUNTER     ; Increment counter
        CALL DISPLAY     ; Update display
        JMP START        ; Repeat indefinitely

    COUNTER PROC
        MOV AL, COUNT    ; Load count into AL register
        INC AL           ; Increment count
        CMP AL, 60       ; Check if count is 60
        JB SKIP          ; Jump if below 60
        XOR AL, AL       ; Reset count to 0
    SKIP:
        MOV COUNT, AL    ; Save count back to memory
        RET
    COUNTER ENDP

    DISPLAY PROC
        MOV BL, COUNT    ; Load count into BL register
        MOV CL, 10       ; Set divisor to 10
        MOV SI, OFFSET DISP ; Set pointer to display buffer

        ; Convert count to BCD and store in display buffer
        MOV AH, 0
        DIV CL
        MOV [SI+3], AH
        MOV AH, 0
        DIV CL
        MOV [SI+2], AH
        MOV AH, 0
        DIV CL
        MOV [SI+1], AH
        MOV AH, 0
        DIV CL
        MOV [SI], AH

        ; Output display buffer to screen
        MOV AH, 2        ; Set cursor position to row 2, column 1
        MOV BH, 0        ; Display page 0
        MOV DH, 1
        MOV DL, 0
        INT 10H

        MOV CX, 4        ; Loop 4 times for each digit
        MOV SI, OFFSET DISP ; Set pointer to display buffer
    DISP_LOOP:
        MOV DL, [SI]     ; Load digit into DL register
        ADD DL, 30H      ; Convert digit to ASCII
        MOV AH, 2        ; Output digit to screen
        INT 10H

        INC SI           ; Move to next digit in display buffer
        LOOP DISP_LOOP   ; Repeat for all 4 digits

        RET
    DISPLAY ENDP

    MAIN ENDP
    END MAIN

这个程序使用了两个子程序：`COUNTER` 和 `DISPLAY`。`COUNTER` 用于递增计数器 `COUNT`，每秒钟递增一次，最大值为 59。`DISPLAY` 用于将 `COUNT` 的值转换成 BCD 码，并显示在屏幕上。程序会一直运行，直到用户按下任意键退出程序。