Godsight的博客

对Intel8086加电或复位的时候，CS=0xFFFF,IP=0x0000,处理机执行指令的时候是从低地址到高地址，这个地址距离内存顶部0xFFFFF,只差16个字节，要是IP值超过0x000F,它与CS形成的物理地址就会因为溢出，而变回0x0001;      所以CS=0xFFFF,IP=0x0000,一般是条跳转指令，让指针指向低地址；一个典型的指令是 jmp 0xF000:0xe05

mov ax,0xb800 ;指向文本模式的显示缓冲区mov es,ax;以下显示字符串"Label offest:"mov byte[es:0x00],'L'mov byte[es:0x01],0x07mov byte[es:0x02],'a'mov byte[es:0x03],0x07mov byte[es:0x04],'b'mov byte[es:0x05],0x07mo

jmp near startmytext db 'L',0x07,'a',0x07,'b',0x07,'e',0x07,'l',0x07,' ',0x07,'o',0x07,\'f',0x07,'f',0x07,'s',0x07,'e',0x07,'t',0x07,':',0x07number db 0,0,0,0,0start:mov ax,0x7c0    ;设置数据段