生成EXE之后用Debug加载后，查看寄存器内容如下：
                     ds=0b2d es=0b2d ss=0b3d cs=0b3e ip=0000
                     程序的起始地址的段地址是__3___。
        1、          0b3e
        2、          0b2d
        3、          0b3d    ; ds+10h后才是程序起始段地址(100h 字节的PSP)
        4、          0


下列指令不能执行的是__3___。
        1、          mov ax,10h[bx]
        2、          mov ax,10h[di]
        3、          mov ax,[di+si]
        4、          mov ax,10h[bx][si]



对如下程序要实现将datasg段中的字符串"welcome to masm!"复制到它后续的数据区中，
                     assume cs:codesg,ds:datasg
                     datasg segment
                     db 'welcome to masm!'
                     db '................'
                     datasg ends
                     codesg segment
                     start: mov ax,datasg
                      mov ds,ax
                      mov si,0
                      ________
                      ________
                      mov ax,4c00h
                      int 21h
                     codesg ends
                     end start
                     在空白区域添加的指令序列合理的是__4___。
        1、          mov di,10h
                     mov cx,10h
                     s: mov ax,[si]
                     mov [di],ax        ; 以字为单位复制，循环应该8次
                     add si,2
                     add di,2
                     loop s
        2、          mov di,10h
                     mov cx,8
                     s: mov ax,[si]
                     mov [di],ax
                     inc si                ; 以字为单位复制，增量应为2
                     inc di
                     loop s
        3、          mov ss,ax
                     mov sp,32
                     mov cx,8
                     s: mov ax,[si]
                     push ax        ; 字符顺序反了
                     add si,2
                     loop s
        4、          mov cx,8
                     s: mov ax,[si]
                     mov [si+10h],ax
                     add si,2
                     loop s