http://www.openrce.org/rss/feeds/blog OpenRCE: The Open Reverse Code Engineering Community Wed, 24 Jan 2007 21:52:39 -0600 https://www.openrce.org/blog/view/586/IDC_Quirks fileoffset <email-suppressed@example.com> If trying to get the high dword of an overflow multiply calculation, i.e:<br /> <br /> 0x0aabbcc * 0x0ddeeff = 0x09403 [edx] 83c4b834 [eax]<br /> <br /> Doing something like this in IDC:<br /> <br /> auto a = 0x0aabbcc * 0x0ddeeff;<br /> <br /> will result in 'a' being the lower dword only (0x083c4b834). A workaround for this is to force one of the operands to a floating point constant like such:<br /> <br /> auto a = 11189196.0 * 0x0ddeeff;<br /> <br /> 'a' is now a floating point number. Attempting to shift it right will fail, since IDA attempts to convert the floating point to a long and fails, so we must do it the long way (divide by 0x0ffffffff):<br /> <br /> auto a = (11189196.0 * 0x0ddeeff) / 4294967295.0;<br /> <br /> 'a' is now 0x09403, just what we wanted :)<br /> <br /> If anyone knows a better way to do this, feel free to comment...