1This is reSID, a reverse engineered software emulation of the MOS6581 SID 2(Sound Interface Device). This chip was used in the Commodore 64 computer. 3 4reSID is free software. See the file COPYING for copying permission. 5 6reSID is a C++ library containing a complete emulation of the SID chip. 7This library can be linked into programs emulating the MOS6510 MPU to 8play music made for the Commodore 64 computer. reSID has been successfully 9linked into VICE, a full-fledged Commodore 64 emulator, and SIDPLAY, a 10popular SID tune player. The VICE home page is: 11http://vice-emu.sourceforge.net/ 12A patch for SIDPLAY can be found on the SIDPLAY home page: 13http://www.geocities.com/SiliconValley/Lakes/5147/ 14 15Various SID emulators exist, however reSID should still be of great 16interest to Commodore 64 nostalgics. The emulator engine is cycle-based, 17emulating the internal operations of the SID chip. SID's audio filter is 18modeled as an actual two-integrator-loop biquadratic filter circuit. 19The engine has been developed based on available information on SID, sampling 20of the OSC3 and ENV3 registers, filter theory, and meticulous testing. 21In short, a scientific approach has been taken to model the SID chip as 22accurately as possible. 23 24To our knowledge reSID is by far the most accurate SID emulator ever created. 25This comes at a price; what is considered a fairly fast CPU at the time of 26this writing is needed to run the emulator. 27