sm64pc/lib/src/__osSiRawReadIo.c

#include "libultra_internal.h"
#include "hardware.h"
s32 __osSiRawReadIo(void *a0, u32 *a1) {
    if (__osSiDeviceBusy())
        return -1;
    *a1 = HW_REG((u32) a0, u32);
    return 0;
}