Interrupts now functional

src/kernel/kernel.c

@@ -1,8 +1,7 @@
 #include "./platform/drivers/ports.h"
 #include "print.h"
 #include "./platform/types.h"
-#include "./platform/interrupts/idt.h"
+#include "./platform/interrupts/int.h"
-#include "./platform/interrupts/isr.h"
 
 void dummy_test_entrypoint() {}
 
@@ -48,4 +47,8 @@ void main() {
     print_str("This program is provided \"as-is\" and no express or implied warranty is provided.\n");
     print_str("The full license can be found at /sys/LICENCE on this system or ./LICENCE in the source tree.\n");
 
+    idt_init();
+    kernel_msg_ok("Interrupts initialized");
+
+    __asm__ __volatile__("int $2");
 }

src/kernel/platform/interrupts/int.c

@@ -0,0 +1,29 @@
+#include "int.h"
+#include "../../print.h"
+
+void exception_handler() {
+    print_str("I");
+}
+
+void idt_set_descriptor(u8 vector, void* isr, u8 flags) {
+    idt_entry_t* descriptor = &idt[vector];
+ 
+    descriptor->isr_low        = (u32)isr & 0xFFFF;
+    descriptor->kernel_cs      = 0x08; // this value can be whatever offset your kernel code selector is in your GDT
+    descriptor->attributes     = flags;
+    descriptor->isr_high       = (u32)isr >> 16;
+    descriptor->reserved       = 0;
+}
+
+void idt_init() {
+    idtr.base = (u32)&idt[0];
+    idtr.limit = (u16)sizeof(idt_entry_t) * 256 - 1;
+ 
+    for (u8 vector = 0; vector < 32; vector++) {
+        idt_set_descriptor(vector, isr_stub_table[vector], 0x8E);
+        isr_stub_table[vector] = TRUE;
+    }
+ 
+    __asm__ volatile ("lidt %0" : : "m"(idtr)); // load the new IDT
+    __asm__ volatile ("sti"); // set the interrupt flag
+}

src/kernel/platform/interrupts/int.h

@@ -0,0 +1,33 @@
+#ifndef INT_H
+#define INT_H
+
+#include "../types.h"
+
+typedef struct {
+	u16 isr_low;      // The lower 16 bits of the ISR's address
+	u16 kernel_cs;    // The GDT segment selector that the CPU will load into CS before calling the ISR
+	u8  reserved;     // Set to zero
+	u8  attributes;   // Type and attributes; see the IDT page
+	u16 isr_high;     // The higher 16 bits of the ISR's address
+} __attribute__((packed)) idt_entry_t;
+
+__attribute__((aligned(0x10))) 
+static idt_entry_t idt[256]; // Create an array of IDT entries; aligned for performance
+
+typedef struct {
+	u16	limit;
+	u32	base;
+} __attribute__((packed)) idtr_t;
+
+static idtr_t idtr;
+
+__attribute__((noreturn))
+void exception_handler(void);
+
+void idt_set_descriptor(u8 vector, void* isr, u8 flags);
+
+extern void* isr_stub_table[];
+ 
+void idt_init(void);
+
+#endif

src/kernel/platform/interrupts/int_lowlevel.asm

@@ -0,0 +1,54 @@
+%macro isr_err_stub 1
+isr_stub_%+%1:
+    call exception_handler
+    iret 
+%endmacro
+; if writing for 64-bit, use iretq instead
+%macro isr_no_err_stub 1
+isr_stub_%+%1:
+    call exception_handler
+    iret
+%endmacro
+
+extern exception_handler
+isr_no_err_stub 0
+isr_no_err_stub 1
+isr_no_err_stub 2
+isr_no_err_stub 3
+isr_no_err_stub 4
+isr_no_err_stub 5
+isr_no_err_stub 6
+isr_no_err_stub 7
+isr_err_stub    8
+isr_no_err_stub 9
+isr_err_stub    10
+isr_err_stub    11
+isr_err_stub    12
+isr_err_stub    13
+isr_err_stub    14
+isr_no_err_stub 15
+isr_no_err_stub 16
+isr_err_stub    17
+isr_no_err_stub 18
+isr_no_err_stub 19
+isr_no_err_stub 20
+isr_no_err_stub 21
+isr_no_err_stub 22
+isr_no_err_stub 23
+isr_no_err_stub 24
+isr_no_err_stub 25
+isr_no_err_stub 26
+isr_no_err_stub 27
+isr_no_err_stub 28
+isr_no_err_stub 29
+isr_err_stub    30
+isr_no_err_stub 31
+
+global isr_stub_table
+isr_stub_table:
+%assign i 0 
+%rep    32 
+    dd isr_stub_%+i ; use DQ instead if targeting 64-bit
+%assign i i+1 
+%endrep
+