From 30d6e8f850d2fe26fffdeef0c38fc627ef8bab9a Mon Sep 17 00:00:00 2001
From: "Anna (navi) Figueiredo Gomes" <navi@vlhl.dev>
Date: Wed, 13 Dec 2023 13:24:48 +0100
Subject: initial commit

currently with:
booted via multiboot 1
protected mode to long mode boostrap code
vga used for outputting
gdt and idt set up
identity paging for the whole memory reported by multiboot
pic and ps/2 set up
acpi code exists but is broken
---
 src/idt.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 src/idt.c

(limited to 'src/idt.c')

diff --git a/src/idt.c b/src/idt.c
new file mode 100644
index 0000000..a78847d
--- /dev/null
+++ b/src/idt.c
@@ -0,0 +1,110 @@
+#include <stdbool.h>
+#include <idt.h>
+#include <vga.h>
+#include <mem.h>
+
+extern void idt_load();
+
+struct idt_entry {
+	uint16_t offset_low;
+	uint16_t sel;
+	uint8_t ist;
+	uint8_t flags;
+	uint16_t offset_middle;
+	uint32_t offset_high;
+	uint32_t reserved;
+} __attribute__((packed));
+
+struct idt {
+	uint16_t limit;
+	uint64_t base;
+} __attribute__((packed));
+
+struct idt_entry idt[256];
+struct idt idt_ptr;
+static void (*handlers[256])(uint64_t, uint64_t) = { 0 };
+static const char *exception_msg[] = {
+	"Division By Zero Exception",
+	"Debug Exception",
+	"Non Maskable Interrupt Exception",
+	"Breakpoint Exception",
+	"Into Detected Overflow Exception",
+	"Out of Bounds Exception",
+	"Invalid Opcode Exception",
+	"No Coprocessor Exception",
+	"Double Fault Exception",
+	"Coprocessor Segment Overrun Exception",
+	"Bad TSS Exception",
+	"Segment Not Present Exception",
+	"Stack Fault Exception",
+	"General Protection Fault Exception",
+	"Page Fault Exception",
+	"Unknown Interrupt Exception",
+	"Coprocessor Fault Exception",
+	"Alignment Check Exception (486+)",
+	"Machine Check Exception (Pentium/586+)",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+	"Reserved Exceptions",
+};
+
+
+void exception_handler(uint64_t num, uint64_t error) {
+	vga_puts("\n\neto bleh: ");
+	vga_puts(exception_msg[num]);
+	vga_puts("\nerror info: ");
+	vga_putx(error);
+	while (1);
+}
+
+void interrupt_handler(uint64_t num, uint64_t data) {
+	handlers[num](num, data);
+}
+
+void idt_set_isr(uint8_t num, uint64_t offset, uint16_t sel, uint8_t flags) {
+	idt[num] = (struct idt_entry) {
+		.offset_low = offset & 0xFFFF,
+		.offset_middle = (offset >> 16) & 0xFFFF,
+		.offset_high = (offset >> 32) & 0xFFFFFFFF,
+		.sel = sel,
+		.ist = 0,
+		.flags = flags,
+		.reserved = 0,
+	};
+}
+
+void idt_init() {
+	idt_ptr.limit = (sizeof(struct idt_entry) * 256) - 1;
+	idt_ptr.base = (uint64_t) &idt;
+	memset(idt, 0, (sizeof(struct idt_entry) * 256));
+	idt_load();
+
+	for (size_t i = 0; i < 32; i++) {
+		idt_set_isr(i, isr_table[i], 0x08, 0x8E);
+		handlers[i] = exception_handler;
+	}
+}
+
+bool idt_register_isr(size_t num, void (*func)(uint64_t, uint64_t)) {
+	if (handlers[num])
+		return false;
+	handlers[num] = func;
+	return true;
+}
+
+bool idt_remove_isr(size_t num, void (*func)(uint64_t, uint64_t)) {
+	if (handlers[num] != func)
+		return false;
+	handlers[num] = NULL;
+	return true;
+}
-- 
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