In this paper, we present a practical processor co-simulation framework for not only RTL simulation but also gate/transistor level simulation, and even chip evaluation with an LSI tester. Our framework includes an off-chip system call emulation mechanism, which handles system calls to evaluate and verify the processor design with general benchmark programs without pseudo-circuits in the processor design. Therefore, our framework can be consistently used from RTL design to chip fabrication. We also propose a checkpoint mechanism that resumes a program from a pre-created checkpoint. This mechanism is not affected by the non-deterministic problem on a multi-core processor. Moreover, we propose a cache warming mechanism when resuming from a checkpoint.