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computer sience fundermantals

80×86汇编拾遗

1.入栈指令:PUSH SRC;W

只允许字操作。

2.MUL SRC ;B/W

SRC绝不允许使用立即数和段寄存器。

3.DIV SRC

如果除数为0,或者在8位数除时商超过8位,或者在16位除时商超过16位,则认为是除溢出,产生0号中断。

4.不要忘记跳转标号和跳转指令;

5.A division can result in two different types of errors:one is an attempt to divide by zero and the other is a divide overflow.A divide overflow occurs when a small number divides into a large number.For example,suppose that AX = 3000 and that it is diveded by 2.Because the quotient for an 8-bit appears in AL,the result of 1500 causes a dived overflow because the 1500 does not fit into AL.

6.寄存器间接寻址方式:操作数的有效地址存放在基址寄存器BX,BP或者变址寄存器SI,DI中。

7.POP DST ;W

DST是出栈时字操作数的地址,初了立即数和CS段寄存器之外,16位寄存器、段寄存器(DS,ES,SS)和各种寻址方式的存储器操作数都可以作为出栈的字操作数的目的操作数。

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