怎样用汇编程序语言将内存1000H开始的100个字节单元的内容清零

请用汇编语言程序实现，谢谢！

data segment
org 1000h
buff db 100(0)
data ends
code segment
assume cs:code,ds:data
start:mov ax,data
mov ds,ax
lea bx,buff
mov cx,100
next:
mov byte ptr [bx],0
inc bx
loop next
mov ah,1
int 21h
mov ax,4c00h
int 21h
code ends
end start

code segment assume cs:code,ds:code,es:code org 800h s1: mov bx,1000h mov ax,0000h mov cx,0020h l1: mov [bx],ax inc bx inc bx loop l1 jmp $ code ends end s1