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/pic.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 src/pic.c

(limited to 'src/pic.c')

diff --git a/src/pic.c b/src/pic.c
new file mode 100644
index 0000000..ad2c15d
--- /dev/null
+++ b/src/pic.c
@@ -0,0 +1,107 @@
+#include <nrvn.h>
+#include <pic.h>
+#include <idt.h>
+#include <vga.h>
+
+extern void toggle_interrupts(bool enable);
+
+#define pic1 0x20
+#define pic2 0xA0
+#define pic1_d (pic1 + 1)
+#define pic2_d (pic2 + 2)
+
+void pic_remap(uint32_t offset1, uint32_t offset2) {
+	uint8_t a1, a2;
+
+	a1 = inb(pic1_d);
+	a2 = inb(pic2_d);
+
+	outb(pic1, 0x10 | 0x01);
+	io_wait();
+	outb(pic2, 0x10 | 0x01);
+	io_wait();
+	outb(pic1_d, offset1);
+	io_wait();
+	outb(pic2_d, offset2);
+	io_wait();
+	outb(pic1_d, 4);
+	io_wait();
+	outb(pic2_d, 2);
+	io_wait();
+
+	outb(pic1_d, 0x01);
+	io_wait();
+	outb(pic2_d, 0x01);
+	io_wait();
+
+	outb(pic1_d, a1);
+	outb(pic2_d, a2);
+}
+
+void pic_set_mask(uint8_t irq_line) {
+	uint32_t port;
+	uint8_t value;
+
+	if (irq_line < 8)
+		port = pic1_d;
+	else {
+		port = pic2_d;
+		irq_line -= 8;
+	}
+	value = inb(port) | (1 << irq_line);
+	outb(port, value);
+}
+
+void pic_clear_mask(uint8_t irq_line) {
+	uint32_t port;
+	uint8_t value;
+
+	if (irq_line < 8)
+		port = pic1_d;
+	else {
+		port = pic2_d;
+		irq_line -= 8;
+	}
+	value = inb(port) & ~(1 << irq_line);
+	outb(port, value);
+}
+
+void pic_set_all_masks(void) {
+	outb(pic1_d, 0xFF);
+	outb(pic2_d, 0xFF);
+}
+
+void pic_clear_all_masks(void) {
+	outb(pic1_d, 0x00);
+	outb(pic2_d, 0x00);
+}
+
+void pic_eoi(uint8_t irq) {
+	if (irq >= 8)
+		outb(pic2, 0x20);
+	outb(pic1, 0x20);
+}
+
+void keyboard_handler(uint64_t num, uint64_t _unused) {
+	(void)num;
+	(void)_unused;
+	uint8_t key = inb(0x60);
+	vga_puts("key pressed: ");
+	vga_putx(key);
+	vga_putc('\n');
+	pic_eoi(0x1);
+}
+
+void pic_init(void) {
+	pic_set_all_masks();
+	pic_clear_mask(1);
+	//pic_clear_mask(12);
+	pic_remap(32, 40);
+
+	for (size_t i = 32; i < 48; i++)
+		idt_set_isr(i, isr_table[i], 0x08, 0x8E);
+
+	idt_register_isr(33, keyboard_handler);
+
+	toggle_interrupts(true);
+}
-- 
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