The DIGIC board contains an x86 compatible processor (NEC V30 emulation) running Datalight ROM-DOS and only S1IS running VxWorks and two other chips (the image processor itself and a Motorola 68HC12).
The DIGIC II and DIGIC III ASICs contain embedded 32-bit ARM architecture processors. Until around 2007, Canon point-and-shoot cameras ran a VxWorks-based operating system, but recent cameras are based on the DRYOS operating system developed in-house by Canon.