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Re: Intel assembly questions
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Re: Intel assembly questions


  • Subject: Re: Intel assembly questions
  • From: Jonas Maebe <email@hidden>
  • Date: Wed, 18 Jan 2006 20:45:43 +0100


On 18 Jan 2006, at 20:31, Dave Camp wrote:

I've started porting some cross-platform Windows/Mac code that has some Intel inline assembly and I've got a couple of questions:

First, Xcode gives me the impression that there are two different ways to compile the assembly: GCC and NASM. Is that correct?

The real names are respectively AT&T and Intel.

MainLoop:
        movzx       eax, byte Ptr [esi+4]
...

The last line is the issue. I assume the original syntax is trying to say 'treat [esi+4] as a byte pointer". Xcode does not like the "byte Ptr" operands.

"byte ptr" is Intel style only.

Removing those causes the following error: No such 386 instruction: movzl

What is the replacement syntax for "byte Ptr"?

In AT&T style, the operand size is always added to the instruction. In this case, the above should become


movzbl 4(%esi),êx

Is there some documentation that covers platform syntax differences like this that I have missed?

Here's a short overview of the most important differences between Intel and AT&T style:
http://personales.mundivia.es/jap/djasm.htm



Jonas _______________________________________________ Do not post admin requests to the list. They will be ignored. Xcode-users mailing list (email@hidden) Help/Unsubscribe/Update your Subscription: This email sent to email@hidden
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