推64位英特尔OSX [英] push on 64bit intel osx
问题描述
我想如下堆栈推64位地址，
I want to push 64 bit address on stack as below,
__asm("pushq $0x1122334455667788");
但我得到的编译错误，我只能在下列方式推，
But I get compilation error and I can only push in following way,
__asm("pushq $0x11223344");
有人可以帮助我了解我的错误？
Can someone help me understand my mistake?
我是新来组装，所以请原谅我，如果我的问题听起来很愚蠢。
I am new to assembly, so please excuse me if my question sounds stupid.
推荐答案
X86-64有一些有趣的怪癖，这是不是就算你熟悉的32位x86 ...
x86-64 has some interesting quirks, which aren't obvious even if you're familiar with 32-bit x86...
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大多数指令只能取32位立即值，如果在64位环境中使用该符号扩展到64位。 （指令编码门店只有32位。）
Most instructions can only take a 32-bit immediate value, which is sign-extended to 64 bits if used in a 64-bit context. (The instruction encoding stores only 32 bits.)
这意味着你可以在范围内使用 pushq 为immedate值为0x0 - 为0x7FFFFFFF （即正符号32位值这是符号扩展0位）或 0xffffffff80000000 - 0xffffffffffffffff ）（即负签署了符号扩展与1位）的32位值。但你不能使用的值超出这个范围（因为他们不能重新$ P $的指令编码psented）。
This means that you can use pushq for immedate values in the range 0x0 - 0x7fffffff (i.e. positive signed 32-bit values which are sign-extended with 0 bits) or 0xffffffff80000000 - 0xffffffffffffffff) (i.e. negative signed 32-bit values which are sign-extended with 1 bits). But you cannot use values outside this range (as they cannot be represented in the instruction encoding).
MOV 是一个特殊情况：有这需要一个完整的64位立即数的编码。因此，丹尼尔的回答（这可能是你最好的选择）。
mov is a special case: there is an encoding which takes a full 64-bit immediate operand. Hence Daniel's answer (which is probably your best bet).
如果您的真正的不想腐败的寄存器，可以使用较小的值的倍数推。然而，推动两个32位值的明显的事情是行不通的。在64位世界中，推将与64位运算工作（根据上述第1点，如果它是一个立即数）或16位操作数，但不32位操作数（甚至 pushl％eax中无效）。所以，你能做的最好的是4个16位推：
If you really don't want to corrupt a register, you could use multiple pushes of smaller values. However, the obvious thing of pushing two 32-bit values won't work. In the 64-bit world, push will work with a 64 bit operand (subject to point 1 above, if it's an immediate constant), or a 16 bit operand, but not a 32 bit operand (even pushl %eax is not valid). So the best you can do is 4 16-bit pushes:
PUSHW $ 0x1122; PUSHW $ 0x3344; PUSHW $ 0x5566; PUSHW $ 0x7788
这篇关于推64位英特尔OSX的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
