加密与解密（连载2)

电脑白痴

第一节 软件保护 <br><br><br><br>　　软件的破解技术与保护技术这两者之间本身就是矛与盾的关系，它们是在互相斗争中发展进化的。这种技术上的较量归根到底是一种利益的冲突。软件开发者为了维护自身的商业利益，不断地寻找各种有效的技术来保护自身的软件版权，以增加其保护强度，推迟软件被破解的时间；而破解者则或受盗版所带来的高额利润的驱使，或出于纯粹的个人兴趣，而不断制作新的破解工具并针对新出现的保护方式进行跟踪分析以找到相应的破解方法。从理论上说，几乎没有破解不了的保护。对软件的保护仅仅靠技术是不够的，而这最终要靠人们的知识产权意识和法制观念的进步以及生活水平的提高。但是如果一种保护技术的强度强到足以让破解者在软件的生命周期内无法将其完全破解，这种保护技术就可以说是非常成功的。软件保护方式的设计应在一开始就作为软件开发的一部分来考虑，列入开发计划和开发成本中，并在保护强度、成本、易用性之间进行折衷考虑，选择一个合适的平衡点。 <br><br><br><br>　　在桌面操作系统中，微软的产品自然是独霸天下，一般个人用户接触得最多，研究得自然也更多一些。在DOS时代之前就有些比较好的软件保护技术，而在DOS中使用得最多的恐怕要算软盘指纹防拷贝技术了。由于DOS操作系统的脆弱性，在其中运行的普通应用程序几乎可以访问系统中的任何资源，如直接访问任何物理内存、直接读写任何磁盘扇区、直接读写任何I/O端口等，这给软件保护者提供了极大的自由度，使其可以设计出一些至今仍为人称道的保护技术；自Windows 95开始（特别是WinNT和Windows 2000这样严格意义上的多用户操作系统），操作系统利用硬件特性增强了对自身的保护，将自己运行在Ring 0特权级中，而普通应用程序则运行在最低的特权级Ring 3中，限制了应用程序所能访问的资源，使得软件保护技术在一定程度上受到一些限制。开发者要想突破Ring 3的限制，一般需要编写驱动程序，如读写并口上的软件狗的驱动程序等，这增加了开发难度和周期，自然也增加了成本。同时由于Win32程序内存寻址使用的是相对来说比较简单的平坦寻址模式（相应地其采用的PE文件格式也比以前的16-bit的EXE程序的格式要容易处理一些），并且Win32程序大量调用系统提供的API，而Win32平台上的调试器如SoftICE等恰好有针对API设断点的强大功能，这些都给跟踪破解带来了一定的方便。<br><br><br><br><br><br>第二节 8088 汇编速查手册 &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; <br><br><br><br><br><br>一、数据传输指令 <br><br>─────────────────────────────────────── <br>&nbsp; &nbsp; 它们在存贮器和寄存器、寄存器和输入输出端口之间传送数据. <br>&nbsp; &nbsp; 1. 通用数据传送指令. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;MOV &nbsp; &nbsp;传送字或字节. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;MOVSX &nbsp;先符号扩展,再传送. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;MOVZX &nbsp;先零扩展,再传送. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspUSH &nbsp; &nbsp;把字压入堆栈. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspOP &nbsp; &nbsp;把字弹出堆栈. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspUSHA &nbsp;把AX,CX,DX,BX,SP,BP,SI,DI依次压入堆栈. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspOPA &nbsp; &nbsp;把DI,SI,BP,SP,BX,DX,CX,AX依次弹出堆栈. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspUSHAD &nbsp;把EAX,ECX,EDX,EBX,ESP,EBP,ESI,EDI依次压入堆栈. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspOPAD &nbsp;把EDI,ESI,EBP,ESP,EBX,EDX,ECX,EAX依次弹出堆栈. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;BSWAP &nbsp;交换32位寄存器里字节的顺序 <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;XCHG &nbsp; &nbsp;交换字或字节.( 至少有一个操作数为寄存器,段寄存器不可作为操作数) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CMPXCHG 比较并交换操作数.( 第二个操作数必须为累加器AL/AX/EAX ) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;XADD &nbsp; &nbsp;先交换再累加.( 结果在第一个操作数里 ) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;XLAT &nbsp; &nbsp;字节查表转换. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; ── BX 指向一张 256 字节的表的起点, AL 为表的索引值 (0-255,即 <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 0-FFH); 返回 AL 为查表结果. ( [BX+AL]-&gt;AL ) <br>&nbsp; &nbsp; 2. 输入输出端口传送指令. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;IN &nbsp; &nbsp;&nbsp; I/O端口输入. ( 语法: IN 累加器, {端口号│DX} ) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;OUT &nbsp; &nbsp;I/O端口输出. ( 语法: OUT {端口号│DX},累加器 ) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 输入输出端口由立即方式指定时, 其范围是 0-255; 由寄存器 DX 指定时, <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 其范围是 0-65535. <br>&nbsp; &nbsp; 3. 目的地址传送指令. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LEA &nbsp; &nbsp;装入有效地址. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 例: LEA DX,string &nbsp;;把偏移地址存到DX. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LDS &nbsp; &nbsp;传送目标指针,把指针内容装入DS. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 例: LDS SI,string &nbsp;;把段地址:偏移地址存到DS:SI. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LES &nbsp; &nbsp;传送目标指针,把指针内容装入ES. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 例: LES DI,string &nbsp;;把段地址:偏移地址存到ES &nbsp;I. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LFS &nbsp; &nbsp;传送目标指针,把指针内容装入FS. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 例: LFS DI,string &nbsp;;把段地址:偏移地址存到FS &nbsp;I. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LGS &nbsp; &nbsp;传送目标指针,把指针内容装入GS. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 例: LGS DI,string &nbsp;;把段地址:偏移地址存到GS &nbsp;I. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LSS &nbsp; &nbsp;传送目标指针,把指针内容装入SS. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 例: LSS DI,string &nbsp;;把段地址:偏移地址存到SS &nbsp;I. <br>&nbsp; &nbsp; 4. 标志传送指令. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LAHF &nbsp; &nbsp;标志寄存器传送,把标志装入AH. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;SAHF &nbsp; &nbsp;标志寄存器传送,把AH内容装入标志寄存器. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspUSHF &nbsp;标志入栈. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspOPF &nbsp; &nbsp;标志出栈. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspUSHD &nbsp;32位标志入栈. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbspOPD &nbsp; &nbsp;32位标志出栈. <br><br><br><br>二、算术运算指令 <br><br>─────────────────────────────────────── <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;　　ADD &nbsp; &nbsp;加法. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;ADC &nbsp; &nbsp;带进位加法. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;INC &nbsp; &nbsp;加 1. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;AAA &nbsp; &nbsp;加法的ASCII码调整. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;DAA &nbsp; &nbsp;加法的十进制调整. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;SUB &nbsp; &nbsp;减法. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;SBB &nbsp; &nbsp;带借位减法. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;DEC &nbsp; &nbsp;减 1. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;NEC &nbsp; &nbsp;求反(以 0 减之). <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CMP &nbsp; &nbsp;比较.(两操作数作减法,仅修改标志位,不回送结果). <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;AAS &nbsp; &nbsp;减法的ASCII码调整. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;DAS &nbsp; &nbsp;减法的十进制调整. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;MUL &nbsp; &nbsp;无符号乘法. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;IMUL &nbsp; &nbsp;整数乘法. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 以上两条,结果回送AH和AL(字节运算),或DX和AX(字运算), <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;AAM &nbsp; &nbsp;乘法的ASCII码调整. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;DIV &nbsp; &nbsp;无符号除法. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;IDIV &nbsp; &nbsp;整数除法. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 以上两条,结果回送: <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;商回送AL,余数回送AH, (字节运算); <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 或 &nbsp;商回送AX,余数回送DX, (字运算). <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;AAD &nbsp; &nbsp;除法的ASCII码调整. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CBW &nbsp; &nbsp;字节转换为字. (把AL中字节的符号扩展到AH中去) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CWD &nbsp; &nbsp;字转换为双字. (把AX中的字的符号扩展到DX中去) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CWDE &nbsp; &nbsp;字转换为双字. (把AX中的字符号扩展到EAX中去) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CDQ &nbsp; &nbsp;双字扩展. &nbsp; &nbsp;(把EAX中的字的符号扩展到EDX中去) <br><br><br><br>三、逻辑运算指令 <br><br>─────────────────────────────────────── <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;　　AND &nbsp; &nbsp;与运算. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;OR &nbsp; &nbsp;&nbsp; 或运算. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;XOR &nbsp; &nbsp;异或运算. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;NOT &nbsp; &nbsp;取反. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;TEST &nbsp; &nbsp;测试.(两操作数作与运算,仅修改标志位,不回送结果). <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;SHL &nbsp; &nbsp;逻辑左移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;SAL &nbsp; &nbsp;算术左移.(=SHL) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;SHR &nbsp; &nbsp;逻辑右移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;SAR &nbsp; &nbsp;算术右移.(=SHR) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;ROL &nbsp; &nbsp;循环左移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;ROR &nbsp; &nbsp;循环右移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;RCL &nbsp; &nbsp;通过进位的循环左移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;RCR &nbsp; &nbsp;通过进位的循环右移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 以上八种移位指令,其移位次数可达255次. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;移位一次时, 可直接用操作码. &nbsp;如 SHL AX,1. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;移位&gt;1次时, 则由寄存器CL给出移位次数. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 如 &nbsp;MOV CL,04 <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;SHL AX,CL <br><br><br><br>四、串指令 <br><br>─────────────────────────────────────── <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; 　DS:SI &nbsp;源串段寄存器 &nbsp;:源串变址. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; ES &nbsp;I &nbsp;目标串段寄存器:目标串变址. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; CX &nbsp; &nbsp;&nbsp; 重复次数计数器. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; AL/AX &nbsp;扫描值. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; D标志 &nbsp;0表示重复操作中SI和DI应自动增量; 1表示应自动减量. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; Z标志 &nbsp;用来控制扫描或比较操作的结束. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;MOVS &nbsp; &nbsp;串传送. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; ( MOVSB &nbsp;传送字符. &nbsp; &nbsp;MOVSW &nbsp;传送字. &nbsp; &nbsp;MOVSD &nbsp;传送双字. ) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CMPS &nbsp; &nbsp;串比较. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; ( CMPSB &nbsp;比较字符. &nbsp; &nbsp;CMPSW &nbsp;比较字. ) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;SCAS &nbsp; &nbsp;串扫描. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; 把AL或AX的内容与目标串作比较,比较结果反映在标志位. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LODS &nbsp; &nbsp;装入串. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; 把源串中的元素(字或字节)逐一装入AL或AX中. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; ( LODSB &nbsp;传送字符. &nbsp; &nbsp;LODSW &nbsp;传送字. &nbsp; &nbsp;LODSD &nbsp;传送双字. ) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;STOS &nbsp; &nbsp;保存串. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp; 是LODS的逆过程. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;REP &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 当CX/ECX&lt;&gt;0时重复. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;REPE/REPZ &nbsp; &nbsp;&nbsp; 当ZF=1或比较结果相等,且CX/ECX&lt;&gt;0时重复. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;REPNE/REPNZ &nbsp; &nbsp;当ZF=0或比较结果不相等,且CX/ECX&lt;&gt;0时重复. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;REPC &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;当CF=1且CX/ECX&lt;&gt;0时重复. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;REPNC &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;当CF=0且CX/ECX&lt;&gt;0时重复. <br><br><br><br>五、程序转移指令 <br><br>─────────────────────────────────────── <br>&nbsp; &nbsp; 　1&gt;无条件转移指令 (长转移) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JMP &nbsp; &nbsp;无条件转移指令 <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CALL &nbsp; &nbsp;过程调用 <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;RET/RETF过程返回. <br>&nbsp; &nbsp; 2&gt;条件转移指令 (短转移,-128到+127的距离内) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;( 当且仅当(SF XOR OF)=1时,OP1&lt;OP2 ) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JA/JNBE 不小于或不等于时转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JAE/JNB 大于或等于转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JB/JNAE 小于转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JBE/JNA 小于或等于转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 以上四条,测试无符号整数运算的结果(标志C和Z). <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JG/JNLE 大于转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JGE/JNL 大于或等于转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JL/JNGE 小于转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JLE/JNG 小于或等于转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; 以上四条,测试带符号整数运算的结果(标志S,O和Z). <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JE/JZ &nbsp;等于转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JNE/JNZ 不等于时转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JC &nbsp; &nbsp;&nbsp; 有进位时转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JNC &nbsp; &nbsp;无进位时转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JNO &nbsp; &nbsp;不溢出时转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JNP/JPO 奇偶性为奇数时转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JNS &nbsp; &nbsp;符号位为 &quot;0&quot; 时转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JO &nbsp; &nbsp;&nbsp; 溢出转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JP/JPE &nbsp;奇偶性为偶数时转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JS &nbsp; &nbsp;&nbsp; 符号位为 &quot;1&quot; 时转移. <br>&nbsp; &nbsp; 3&gt;循环控制指令(短转移) <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LOOP &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; CX不为零时循环. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LOOPE/LOOPZ &nbsp; &nbsp;CX不为零且标志Z=1时循环. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LOOPNE/LOOPNZ &nbsp;CX不为零且标志Z=0时循环. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JCXZ &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;&nbsp; CX为零时转移. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;JECXZ &nbsp; &nbsp;&nbsp; &nbsp;&nbsp; &nbsp;ECX为零时转移. <br>&nbsp; &nbsp; 4&gt;中断指令 <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;INT &nbsp; &nbsp;中断指令 <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;INTO &nbsp; &nbsp;溢出中断 <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;IRET &nbsp; &nbsp;中断返回 <br>&nbsp; &nbsp; 5&gt;处理器控制指令 <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;HLT &nbsp; &nbsp;处理器暂停, 直到出现中断或复位信号才继续. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;WAIT &nbsp; &nbsp;当芯片引线TEST为高电平时使CPU进入等待状态. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;ESC &nbsp; &nbsp;转换到外处理器. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;LOCK &nbsp; &nbsp;封锁总线. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;NOP &nbsp; &nbsp;空操作. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;STC &nbsp; &nbsp;置进位标志位. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CLC &nbsp; &nbsp;清进位标志位. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CMC &nbsp; &nbsp;进位标志取反. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;STD &nbsp; &nbsp;置方向标志位. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CLD &nbsp; &nbsp;清方向标志位. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;STI &nbsp; &nbsp;置中断允许位. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;CLI &nbsp; &nbsp;清中断允许位. <br><br><br><br>六、伪指令 <br><br>─────────────────────────────────────── <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;　　DW &nbsp; &nbsp;&nbsp; 定义字(2字节). <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;PROC &nbsp; &nbsp;定义过程. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;ENDP &nbsp; &nbsp;过程结束. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;SEGMENT 定义段. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;ASSUME &nbsp;建立段寄存器寻址. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;ENDS &nbsp; &nbsp;段结束. <br>&nbsp; &nbsp; &nbsp;&nbsp; &nbsp;END &nbsp; &nbsp;程序结束.<br><br>