I just merged branch that bring some examples of using Standard Peripheral Library from C code. You can found these examples at this link.
There are only three simple examples at now. GPIO, UART and VGA. It is mostly because many features request work with interrupts. But interrupts are not implemented in vbcc backend yet. I will add this feature probably with new CPU core because I'm going to significantly change interrupt mechanism.
But now, thank to these examples, I was able to chatch many bugs in SPL and even more in compiler backend itself. I also added some more simple optimizations in generated assembly.