Initial checkin of toy OS project.HEADmaster

1 files changed, 230 insertions, 0 deletions

diff --git a/kernel/hal/interrupts.c b/kernel/hal/interrupts.c
new file mode 100644
index 0000000..94f2528
--- /dev/null
+++ b/kernel/hal/interrupts.c
@@ -0,0 +1,230 @@
+//+----------------------------------------------------------------------------
+//
+// File:     interrupts.c
+//
+// Module:   
+//
+// Synopsis: 
+//
+// Created:  sgasch  6 Jul 2003
+//
+//+----------------------------------------------------------------------------
+
+#include "kernel.h"
+#include "hal.h"
+#include "rtl.h"
+#include "interrupts.h"
+
+IDT_ENTRY g_IDT[NUM_IDT_ENTRIES];
+INTERRUPT_HANDLER g_InterruptHandlerTable[NUM_IDT_ENTRIES];
+ULONG g_uInterruptsEnabled = 0;
+
+void
+HalEnableInterrupts(void)
+{
+    g_uInterruptsEnabled++;
+    ASSERT(g_uInterruptsEnabled == 1);
+
+    __asm__ __volatile__ (
+        "sti"
+        );
+}
+
+void
+HalDisableInterrupts(void)
+{
+    g_uInterruptsEnabled--;
+    ASSERT(g_uInterruptsEnabled == 0);
+
+    __asm__ __volatile__ (
+        "cli"
+        );
+}
+
+
+//+----------------------------------------------------------------------------
+//
+// Function:  DoNothing
+//
+// Synopsis:  The default interrupt handler, do nothing
+//
+// Arguments: INTERRUPT_STATE *p
+//            
+// Returns:   void
+//
+//+----------------------------------------------------------------------------
+void HalDoNothing(INTERRUPT_STATE *p)
+{
+    ;
+}
+
+
+//+----------------------------------------------------------------------------
+//
+// Function:  InterruptSendIrqEoi
+//
+// Synopsis:  Send Interrupt ReQuest End Of Interrupt to the PIC.
+//
+// Arguments: INTERRUPT_STATE *is
+//            
+// Returns:   void
+//
+//+----------------------------------------------------------------------------
+void 
+HalInterruptSendIrqEoi(INTERRUPT_STATE *is)
+{
+    ULONG uIrq;
+    BYTE bCommand;
+    BYTE *p = (BYTE *)0x000B8000;
+
+    *p = '3';
+    *(p + 1) = ' ';
+    
+    if ((is->uIntNum >= FIRST_EXTERNAL_INT) &&
+        (is->uIntNum <= LAST_EXTERNAL_INT))
+    {
+        uIrq = (is->uIntNum - FIRST_EXTERNAL_INT);
+        ASSERT(uIrq >= 0);
+        ASSERT(uIrq <= 15);
+        bCommand = 0x60 | (uIrq & 0x7);
+        
+        if (uIrq < 8)
+        {
+            // EOI to master PIC
+            out(0x20, bCommand);
+            HalIoDelay();
+        }
+        else 
+        {
+            // EOI to slave PIC and cascade line EOI to master PIC
+            out(0xA0, bCommand);
+            out(0x20, 0x62);
+            HalIoDelay();
+        }
+    }
+
+    *p = '4';
+    *(p + 1) = ' ';
+}
+
+//+----------------------------------------------------------------------------
+//
+// Function:  InterruptInitializeGate
+//
+// Synopsis:  Initializes an interrupt gate with given handler address
+//            and descriptor privilege level.
+//
+// Arguments: IDT_ENTRY *pEntry,
+//            void *pPreamble,
+//            ULONG uDpl
+//            
+// Returns:   void
+//
+//+----------------------------------------------------------------------------
+void 
+HalInterruptInitializeGate(IDT_ENTRY *pEntry, 
+                           void *pPreamble,
+                           ULONG uDpl)
+{
+    ULONG u = (ULONG)pPreamble;
+
+    pEntry->i.offsetLow = u & 0xffff;
+    pEntry->i.segmentSelector = (1<<3);
+    pEntry->i.reserved = 0;
+    pEntry->i.signature = 0x70; // == 01110000b
+    pEntry->i.dpl = uDpl;
+    pEntry->i.present = 1;
+    pEntry->i.offsetHigh = u >> 16;
+}
+
+
+//+----------------------------------------------------------------------------
+//
+// Function:  InterruptInstallHandler
+//
+// Synopsis:  Installs an interrupt handler routine for a given IRQ number
+//
+// Arguments: ULONG uInterruptNumber,
+//            INTERRUPT_HANDLER pHandler
+//            
+// Returns:   void
+//
+//+----------------------------------------------------------------------------
+void 
+HalInterruptInstallHandler(ULONG uInterruptNumber,
+                           INTERRUPT_HANDLER pHandler)
+{
+    ASSERT(uInterruptNumber < ARRAY_LENGTH(g_InterruptHandlerTable));
+    
+    g_InterruptHandlerTable[uInterruptNumber] = pHandler;
+}
+
+
+//+----------------------------------------------------------------------------
+//
+// Function:  InterruptInitialize
+//
+// Synopsis:  Initialize the interrupt system
+//
+// Arguments: void
+//            
+// Returns:   void
+//
+//+----------------------------------------------------------------------------
+void 
+HalInitializeInterrupts(void)
+{
+    ULONG uPreambleEntrySize = (ULONG)&HalInterruptHandlerPreambleAfter;
+    ULONG u;
+    ULONG uDpl;
+    USHORT uLimitAndBase[3];
+    BYTE *p;
+
+    //
+    // Determine the size of an interrupt preamble table entry.
+    //
+    uPreambleEntrySize -= (ULONG)&HalInterruptHandlerPreambleBefore;
+
+    //
+    // Set the base interrupt number for each PIC.  See comments in
+    // intsupport.asm.
+    //
+    HalInterruptInitializePICs();
+
+    //
+    // Build interrupt descriptor table
+    //
+    for (u = 0, p = &HalInterruptHandlerPreamble;
+         u < ARRAY_LENGTH(g_IDT);
+         u++, p += uPreambleEntrySize)
+    {
+        uDpl = (u == 0x2E) ? USER_PRIVILEGE : KERNEL_PRIVILEGE;
+
+        HalInterruptInitializeGate(&(g_IDT[u]), p, uDpl);
+        HalInterruptInstallHandler(u, HalDoNothing);
+    }
+
+    //
+    // Install the IDT
+    //
+    u = (ULONG)&(g_IDT);
+    uLimitAndBase[0] = 8 * NUM_IDT_ENTRIES;
+    uLimitAndBase[1] = (USHORT)(u & 0xffff);
+    uLimitAndBase[2] = (USHORT)(u >> 16);
+    
+    HalInterruptLoadIDTR((void *)uLimitAndBase);
+
+    //
+    // Install interrupt handlers
+    //
+    HalInterruptInstallHandler(IRQ0, HalTimerInt);
+    HalInterruptInstallHandler(IRQ1, HalKeyboardInt);
+
+    out(0x21, 0xFC);                          // turn on keyboard and timer
+
+    //
+    // Enable interrupts
+    //
+    HalEnableInterrupts();
+}
+