<p>Hi Eliot, I think I captured everything discussed.</p>
<p>One extra thing though...<br>
I was wondering that if x64 doesn't support _MCW_RC, then the _PC_53 is irrelevant, then our 64-bit VM was using the CPU default 64-bit extended floating point, so was different from our 32-bit VM, but then I found this insight...</p>
<blockquote>
<p>The CPU hardware default is 64-bit precision mode (80-bit long double); Microsoft expects software to set 53-bit mode before any user mode x87 instructions are reached. Microsoft made a change in responsibility for initializing precision mode in the X64 OS. The X64 OS sets 53-bit mode prior to starting your .exe, where the 32-bit OS expected the program to make that initialization.</p>
</blockquote>
<p>If that is how you understand it, I think that explanation would be a useful code comment.</p>

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