如何在`test`指导工作？ [英] How does the `test` instruction work?

问题描述

如果我们有：

test dword ptr [eax], 2000h
je label1:

是否有任何价值比 0 其他DWORD PTR [EAX] 这将使跳发生的呢？

Is there any value other than 0 in dword ptr [eax] that would make the jump take place?

推荐答案

指令的测试就像和指令，唯一的区别是结果不存回至目标操作数。
因此，答案是肯定的。所有二进制数而不是已设置的第13位上的存储器地址[EAX]，或所有的数字present像b'xxxxxxxx XXXXXXXX xx0xxxxx XXXXXXXX'，其中x是0或1，那里恰好是2 ^ 31的数字。

Instruction test works like and instruction, the only difference is that result is not stored back in to the destination operand. So the answer is yes. All binary numbers which not have set the 13th bit on memory address [eax], or all numbers present like b'xxxxxxxx xxxxxxxx xx0xxxxx xxxxxxxx', where x is 0 or 1, there is exactly 2^31 numbers.

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