reSID
reSID is a reverse engineered software emulation of the MOS6581 SID (Sound Interface Device). This chip was used in the Commodore 64 computer. reSID is free software, published under the GNU General Public License.
reSID is a C++ library containing a complete emulation of the SID chip. This library can be linked into programs emulating the MOS6510 MPU to play music made for the Commodore 64 computer. reSID has been linked into VICE (a Commodore 64 emulator), SIDPLAY (a SID tune player), and into the trackers GoatTracker and cheesecutter.