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copied!<p>A comment wasn't enough space. Joe_Muc is correct. You should not stuff code into memory obtained by <code>malloc</code> or <code>new</code>. You will run into problems if you change the page properties of pages that Windows allocates.</p> <p>This isn't a problem becuase using VirtualAlloc() and the related WIn32 APIs is every easy: call <a href="http://msdn.microsoft.com/en-us/library/aa366887.aspx" rel="noreferrer">VirtualAlloc(</a>) and set the <code>flProtect</code> to <code>[PAGE_EXECUTE_READWRITE][2]</code></p> <p>Note, you should probably do three allocations, one guard page, the pages you need for your code, then another guard page. This will give you a little protection from bad code.</p> <p>Also wrap calls to your generated code with <a href="http://msdn.microsoft.com/en-us/library/ms680657(VS.85).aspx" rel="noreferrer">structured exception handling</a>.</p> <p>Next, the Windows X86 ABI (calling conventions) are not well documented (I know, I've looked). There is some info <a href="http://support.microsoft.com/kb/100832" rel="noreferrer">here</a>, <a href="http://msdn.microsoft.com/en-us/library/aa235439(VS.60).aspx" rel="noreferrer">here</a>, <a href="http://www.agner.org/optimize/calling_conventions.pdf" rel="noreferrer">here</a> The best way to see how things work is to look at code generated by the compiler. This is easy to do with the <a href="http://msdn.microsoft.com/en-us/library/367y26c6(VS.80).aspx" rel="noreferrer"><code>\FA</code> switches</a> ( there are four of them).</p> <p>You can find the 64-bit calling conventions <a href="http://msdn.microsoft.com/en-us/library/ms794533.aspx" rel="noreferrer">here</a>.</p> <p>Also, you can still obtain Microsoft's Macro Assembler <a href="http://www.microsoft.com/downloads/details.aspx?familyid=7A1C9DA0-0510-44A2-B042-7EF370530C64&displaylang=en" rel="noreferrer">MASM here</a>. I recommend writing your machine code in MASM and look at its output, then have your machine code generator do similar things. </p> <p><a href="http://www.intel.com/products/processor/manuals/index.htm" rel="noreferrer">Intel's</a> and <a href="http://www.amd.com/us-en/Processors/TechnicalResources/0,,30_182_739_15343,00.html" rel="noreferrer">AMD's</a> processor manuals are good references - get them if you don't have them.</p>

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