UEFI Application - Event

基本上 UEFI 是個單工的系統，它並不支持中斷
而是透過 Event﹝Timer interrupt﹞來達成任務的分配

底下是一個簡單 create Event 的例子
這個 Event 綁定在 1 個 5 秒鐘會觸發 1 次的 Timer 上
不多說，直接來看範例

#include <Library/UefiBootServicesTableLib.h>
#include <stdio.h>
#include <time.h>
//-----------------------------------------------------------------------------
static int g_count = 1;
//-----------------------------------------------------------------------------
void printTime(void)
{
    struct tm *t1;
    time_t ret;

    time(&ret);
    ret += 8 * 60 * 60;
    t1 = gmtime(&ret);

    printf(
        "[%04d-%02d-%02d %02d:%02d:%02d] %02d - in NotifyFunction \n",
        t1->tm_year + 1900,
        t1->tm_mon + 1,
        t1->tm_mday,
        t1->tm_hour,
        t1->tm_min,
        t1->tm_sec,
        g_count
    );
}
//-----------------------------------------------------------------------------
VOID EFIAPI 
NotifyFunction(
  IN  EFI_EVENT  Event,
  IN  VOID       *Context
  )
{
    printTime();

    g_count++;
}
//-----------------------------------------------------------------------------
int main(int argc, char **argv)
{
    EFI_EVENT event;

    gBS->CreateEvent(
        EVT_TIMER | EVT_NOTIFY_SIGNAL,
        TPL_NOTIFY,
        NotifyFunction,
        NULL,
        &event
    );

    // every 5 seconds to trigger
    gBS->SetTimer(event, TimerPeriodic, 50000000);

    do {
        // wait NotifyFunction
    } while(g_count < 10);

    gBS->SetTimer(event, TimerCancel, 0);

    gBS->CloseEvent(event);

    return 0;
}