Running retro software under QEMU, the open source machine emulator and virtualizer. See also the wiki page for the [emulation] tag.
QEMU is a generic and open source machine emulator and virtualizer.
When used as a machine emulator, QEMU can run OSes and programs made for one machine (e.g. an ARM board) on a different machine (e.g. your own PC). By using dynamic translation, it achieves very good performance.
See the emulation tag wiki on guidance as to which emulation questions are on-topic.