什么是在＆QUOT和0x10;莱亚尔为0x10（％EBX），％eax中＆QUOT; x86汇编指令？ [英] What is the 0x10 in the "leal 0x10(%ebx), %eax" x86 assembly instruction?
问题描述
该功能是为0x10的关于这个leal指令是什么？它是一个乘法或添加或别的东西？
What the function is of the 0x10 in regards to this LEAL instruction? Is it a multiply or addition or is something else?
leal 0x10(%ebx), %eax
有人可以请你澄清？这是在Linux机器x86汇编。
Can someone please clarify? This is x86 assembler on a Linux box.
推荐答案
莱亚尔，或执法机关的全称是加载有效地址，它究竟这样的：它做一个地址计算
leal, or lea full name is "Load effective address" and it does exactly this: It does an address calculation.
在你的榜样地址计算很简单，因为它只是增加了一个偏移量EBX和结果存储在EAX：
In your example the address calculation is very simple, because it just adds a offset to ebx and stores the result in eax:
EAX = EBX + 0×10
eax = ebx + 0x10
LEA可以做更多的事情。它可以与常量2,4和8的话，整体和双打地址计算添加寄存器，乘法寄存器。它也可以加一个偏移量。
lea can do a lot more. It can add registers, multiply registers with the constants 2, 4 and 8 for address calculations of words, integers and doubles. It can also add an offset.
需要注意的是执法机关是它永远不会改变标志的方式特殊，即使你使用它作为一个简单的加法就像上面的例子。编译器有时会利用此功能，并通过执法机关替换除了帮调度。这并不少见LEA指令做简单的算术编译code这个原因。
Note that lea is special in the way that it will never modify the flags, even if you use it as a simple addition like in the example above. Compilers sometimes exploit this feature and replace an addition by a lea to help the scheduler. It's not uncommon to see lea instructions doing simple arithmetic in compiled code for that reason.
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