请问调用什么中断可以获取电脑时钟频率

; 文件名：Cpu.Asm
; Dos下 .Com 格式文件

        .model tiny
        .586
        .code
        org 100h
start:
        lea dx,Message          ;显示信息
        mov ah,9
        int 21h

        xor ax,ax
        mov ds,ax
        mov ebx,ds:[46ch]       ;取时间，每55ms该值自动增1
        rdtsc
        mov esi,eax
        mov edi,edx
        mov ecx,ebx
bb:
        cmp ecx,ds:[46ch]
        jz bb

        mov ecx,ds:[46ch]
        rdtsc

        push ecx
        sub ecx,ebx
        sub eax,esi
        sbb edx,edi
        push eax
        push edx
        mov eax,55000     
        mul ecx
        mov ecx,eax
        pop edx
        pop eax
        div ecx
        call dispax
        pop ecx

        mov eax,ecx
        sub eax,ebx
        cmp ax,500      ;约30秒后自动退出
        ja Over
        mov ah,1        ;检测是否有按键
        int 16h
        jz bb
        mov ah,0        ;有，则读按键
        int 16h
Over:
        mov ah,4ch      ;程序结束
        int 21h
        
; 显示ＡＬ代表的ASCII码字符
dispc   proc NEAR
        PUSH AX
        PUSH DX
        MOV AH,2
        MOV DL,AL
        INT 21H
        POP DX
        POP AX
        RET
dispc   endp


;以十进制的形式显示AX的值,显示所占的位数为CX
;若CX的值小于数据的实际宽度则按实际宽度输出
dispax  proc near
        push ax         
        push bx
        push cx
        push dx
        push bp
        mov cx,5        ;输出数据宽度5位
        mov bx,0        ;记录数据实际宽度
        mov bp,10       ;十进制
disp1:
        xor dx,dx
        div bp
        inc bx          ;显示数据的位数增1
        push dx         ;保存余数
        cmp ax,0        ;商为0 ?
        jnz disp1       ;没，继续！
        sub cx,bx       ;要求宽度和实际宽度比较
        jle disp3
        mov al,' '      ;宽度不够，前面补空格
disp2:
        call dispc
        loop disp2
disp3:
        mov cx,bx       ;数据的实际位数送CX
disp4:
        pop ax          ;依次从堆栈中取数并显示
        and al,0fh
        add al,'0'
        call dispc
        loop disp4
        call SetPos
        pop bp          ;恢复寄存器的原值
        pop dx
        pop cx
        pop bx
        pop ax
        ret
dispax  endp

SetPos  proc near       ;调整光标位置
        push ax
        push dx
        push ds
        push cs
        pop ds
        lea dx,Back
        mov ah,9
        int 21h
        pop ds
        pop dx
        pop ax
        ret
SetPos  endp

        Even

Message db 13,10,'Press any key to STOP !',13,10,13,10
        db 'Cpu Speed:       MHz',8,8,8,8
Back    db 8,8,8,8,8,'$'

        end start

;--------------------------------------------------------------
编译链接

D:\Masm615>ml Cpu.asm
Microsoft (R) Macro Assembler Version 6.15.8803
        Patched for you by promethee [ECL] in the year 2001 - enjoy
Copyright (C) Microsoft Corp 1981-2000.  All rights reserved.

Assembling: Cpu.asm

Microsoft (R) Segmented Executable Linker  Version 5.60.339 Dec  5 1994
Copyright (C) Microsoft Corp 1984-1993.  All rights reserved.

Object Modules [.obj]: Cpu.obj /t
Run File []: "
List File [nul.map]: NUL
Libraries [.lib]:
Definitions File [nul.def]:

D:\Masm615>Cpu

Press any key to STOP !

Cpu Speed:  1000 MHz
D:\Masm615>_