>:(where can download a free x86_64 C compiler for windows?
I found xgcc for cygwin(http://aireos.com), but can not use it.
amd64 gcc compiler for windows
Re:amd64 gcc compiler for windows
See http://www.osdev.org/osfaq2/index.php/G ... s-Compiler from the Wiki for building your own GCC AMD64 compiler. (x86_64 section is near the bottom of the page)