sy4-1.asm

来自「硬件电路测试参考数据包」· 汇编 代码 · 共 49 行

;       实验四 (01) 使用微机内8253驱动声音接口          sy4_1.ASM

dseg segment
      freq dw 262,294,330,349,392,440,494,523
      tim  dw 400
dseg  ends
cseg  segment
main  proc far
      assume cs:cseg,ds:dseg
start:
      mov ax,dseg
      mov ds,ax
      mov si,0
again:
      mov di,freq[si]
      mov bx,tim
      call gen
      add si,2
      cmp si,16
      jnz again
      mov ah,4ch
      int 21h
main  endp
gen   proc near
      mov al,0b6h
      out 43h,al
      mov dx,12h
      mov ax,533h*896
      div di
      out 42h,al
      mov al,ah
      out 42h,al
      in al,61h
      mov ah,al
      or al,3
      out 61h,al
wait1:
      mov cx,2801h
delay:
      loop delay
      dec bx
      jnz wait1
      mov al,ah
      out 61h,al
      ret
gen   endp
cseg  ends
      end start