A processing device comprises an instruction memory 120 for storing virtual machine instructions, such as Java byte codes. A processor 112 of the processing device comprises a predetermined micro controller core 114 for executing native instructions from a predetermined set of micro controller specific instructions. The native instructions differ from the virtual machine instructions. The processor 112 is of a type which may request re-feeding of a plurality of native instructions. For instance, the processor 112 may have a pipeline and/or instruction cache which after an interrupt need to be re-filled. The processing device comprises a pre-processor 130 with a converter 132 for converting at least one virtual machine instruction, fetched from the instruction memory, into at least one native instruction. Feeding means 136 of the pre-processor 130 feed native instructions to the micro controller core 114 and re-feed native instructions in response to the processor requesting re-feeding of a number of native instructions. The processing device is a stack oriented machine, and at least the top elements of the stack are mapped onto registers of the processor. The position of the top of the memory stack is preferably indicated using a register of the converter.