stos/amd64: lapic: Add helper to obtain Local APIC ID

Signed-off-by: Chloe M. <chloe@mensia.org>
2026-06-27 14:24:05 -05:00
parent 89e87fc525
commit 1020db0f41
2 changed files with 22 additions and 0 deletions
@@ -236,6 +236,23 @@ MdLapicSendIpi(UCHAR Vector, UCHAR DestId, BOOLEAN LogicalDest,
    LapicRegWrite(Mcb, LAPIC_ICRLO, ((UQUAD)DestId << 32) | IcrLow);
 }

+ULONG
+MdLapicId(VOID)
+{
+    KPCR *ThisCore;
+    MCB *Mcb;
+
+    ThisCore = HalKpcrCurrent();
+    Mcb = &ThisCore->Mcb;
+
+    /* 32-bit when in x2APIC mode */
+    if (Mcb->HasX2Apic) {
+        return LapicRegRead(Mcb, LAPIC_ID) & 0xFFFFFFFF;
+    }
+
+    return (LapicRegRead(Mcb, LAPIC_ID) >> 24) & 0xF;
+}
+
 VOID
 MdLapicInit(KPCR *Kpcr)
 {