oot/src/libultra_boot_O1/piacs.c

#include <global.h>

u32 __osPiAccessQueueEnabled = 0;

OSMesg piAccessBuf;
OSMesgQueue __osPiAccessQueue;

void __osPiCreateAccessQueue(void) {
    __osPiAccessQueueEnabled = 1;
    osCreateMesgQueue(&__osPiAccessQueue, &piAccessBuf, 1);
    osSendMesg(&__osPiAccessQueue, NULL, OS_MESG_NOBLOCK);
}

void __osPiGetAccess(void) {
    OSMesg mesg;

    if (!__osPiAccessQueueEnabled) {
        __osPiCreateAccessQueue();
    }

    osRecvMesg(&__osPiAccessQueue, &mesg, OS_MESG_BLOCK);
}

void __osPiRelAccess(void) {
    osSendMesg(&__osPiAccessQueue, 0, OS_MESG_NOBLOCK);
}