Some of the bytecodes are executed directly, others are translated to microcode sequences, others are implemented in software. From the linked paper: "... dir

Some of the bytecodes are executed directly, others are translated to microcode sequences, others are implemented in software. From the linked paper: "... direct implementation of all bytecodes in hardware is not a useful approach ... Microcode is the native instruction set for JOP. Bytecodes are translated, during their execution, into JOP microcode. This translation merely adds one pipeline stage to the core processor and results in no execution overheads ... 43 of the 201 different bytecodes are implemented by a single microcode instruction, 93 by a microcode sequence, and 40 bytecodes are implemented in Java."