From Rare Gaming Dump

OSReport is a function in the Dolphin SDK and Revolution SDK standard library (defined in the osD.a file), which is typically used to transmit messages about the program's state, such as the current register values when a fatal exception occurs, to the defined output port. The output port is, by default, set to the serial port, but it is recommended to be set to the television screen near the end of program development for convenience. Doing so would require a custom implementation of OSReport, however. The output may also be written to NAND for the purposes of enabling the log to be saved to the SD card, which would require the destination to first be set to NAND with OSReportDestination, and then OSReportFlush to clear the buffer and actually write to NAND.