BITSCOPE design PIC Virtual Machine

The correct appearance of this website is only visible in graphical browsers that support web standards. We try to ensure our content is accessible to any browser but we recommend you upgrade your web browser if you can.
Pic Chip.

The Bitscope PIC is a programmable virtual machine.

  • RISC style instruction set of 42 single byte instructions.
  • Instructions operate on a set of 46 single byte registers.
  • Execution is "live" via the serial port.
  • No programs are stored in Bitscope memory.
  • Programs called scripts define the operation of Bitscope.
  • All instruction execution is atomic which is very important.

A virtual machine design has a number of advantages.

  • Efficiency: each instruction may be highly optimized for performance. A general interpreter like BASIC can do anything - but in a very inefficient way. A virtual machine instruction is compact like assembly code, but may perform an extremely complex task.
  • Modularity: once a register set and basic command set are devised, extensions may be made by adding new instructions to enhance the machine. The original instructions remain the same.
  • Portability: changes to the physical machine (ie PIC) have little impact on the virtual machine design and the software that runs on the virtual machine.

The virtual machine looks like a simple RISC CPU with a set of byte code instructions operating on a set of byte wide registers. Virtual machine programs (scripts) are stored in the host but executed in the virtual machine byte-by-byte as they are received on the serial port.

Because they live in host memory, scripts are not limited to the memory in Bitscope itself. The virtual machine design means you do not need to know PIC programming to program Bitscope.

Consequently it is very easy to program Bitscope.