oot/src/libultra_boot_O2/__osSiRawWriteIo.c

#include <global.h>
#include <ultra64/hardware.h>

s32 __osSiRawWriteIo(void* a0, u32 a1) {
    if (__osSiDeviceBusy()) {
        return -1;
    }
    HW_REG((u32)a0, u32) = a1;
    return 0;
}