CTAOS v6

SysCore/drivers/cpu/idt/idt.asm

@@ -0,0 +1,9 @@
+bits 32
+
+; !!!  IDT  !!!
+; Loads the IDT defined in '_idtp'
+global _i86_IdtLoad
+extern _idtp
+_i86_IdtLoad:
+      lidt [_idtp]
+      ret

SysCore/drivers/cpu/idt/idt.c

@@ -0,0 +1,45 @@
+/******************************************************************
+ *    idt.h  -  INTERRUPT DESCRIPTOR TABLE                        *
+ *      Contains structures and function declarations for IDT     *
+ ******************************************************************/
+#include <system.h>
+#include "idt.h"
+
+extern void i86_IdtLoad();
+/* Declare an IDT of 256 entries.  */
+struct IdtEntry idt[256];
+struct IdtPointer idtp;
+
+/* Use this function to set an entry in the IDT. Alot simpler
+*  than twiddling with the GDT ;) */
+void i86_IdtSetGate(unsigned char num, unsigned long base, unsigned short sel, unsigned char flags)
+{
+    /* The interrupt routine's base address */
+    idt[num].base_lo = (base & 0xFFFF);
+    idt[num].base_hi = (base >> 16) & 0xFFFF;
+
+    /* The segment or 'selector' that this IDT entry will use
+    *  is set here, along with any access flags */
+    idt[num].sel = sel;
+    idt[num].always0 = 0;
+    idt[num].flags = flags;
+}
+
+struct IdtEntry* i86_IdtGetGate(unsigned char num)
+{
+      return &idt[num];
+}
+
+/* Installs the IDT */
+void i86_IdtInstall()
+{
+    /* Sets the special IDT pointer up, just like in 'gdt.c' */
+    idtp.limit = (sizeof (struct IdtEntry) * 256) - 1;
+    idtp.base = (unsigned int)&idt;
+
+    /* Clear out the entire IDT, initializing it to zeros */
+    memset (&idt, 0, sizeof(struct IdtEntry) * 256);
+
+    /* Points the processor's internal register to the new IDT */
+    i86_IdtLoad();
+}

SysCore/drivers/cpu/idt/idt.h

@@ -0,0 +1,31 @@
+/******************************************************************
+ *    idt.h  -  INTERRUPT DESCRIPTOR TABLE                        *
+ *      Contains structures and function declarations for IDT     *
+ ******************************************************************/
+
+#ifndef __IDT_H
+#define __IDT_H
+
+/* Defines an IDT entry */
+struct IdtEntry
+{
+    unsigned short base_lo;
+    unsigned short sel;
+    unsigned char always0;
+    unsigned char flags;
+    unsigned short base_hi;
+} __attribute__((packed));
+
+struct IdtPointer
+{
+    unsigned short limit;
+    unsigned int base;
+} __attribute__((packed));
+
+
+/* This exists in 'start.asm', and is used to load our IDT */
+extern void i86_IdtSetGate(unsigned char num, unsigned long base, unsigned short sel, unsigned char flags);
+extern struct IdtEntry* i86_IdtGetGate(unsigned char num);
+extern void i86_IdtInstall();
+
+#endif