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Created: Wednesday, January 24 2007 21:52.39 CST

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IDC Quirks

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fileoffset

# Views: 2497

If trying to get the high dword of an overflow multiply calculation, i.e:

0x0aabbcc * 0x0ddeeff = 0x09403 [edx] 83c4b834 [eax]

Doing something like this in IDC:

auto a = 0x0aabbcc * 0x0ddeeff;

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:

auto a = 11189196.0 * 0x0ddeeff;

'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):

auto a = (11189196.0 * 0x0ddeeff) / 4294967295.0;

'a' is now 0x09403, just what we wanted :)

If anyone knows a better way to do this, feel free to comment...

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