Syncboot/kernel/kernel.c

/************************
 *** Team Kitty, 2019 ***
 ***       Sync       ***
 ***********************/

/* This file contains the entry point
 * to the kernel. This section consists
 * mainly of bootloading functions.
 *
 * Graphics and memory will be setup
 * at later stages.
 */
 
//#include <stdio.h>
#include <kernel.h>
#include <kernel/tty.h>
#include <kernel/serial.h>
#include <kernel/descriptor_tables.h>

void gdb_end() {} /* GDB Debugging stump */

int kernel_main(void) {
	/* The kernel is started in 32-bit protected mode by the ASM. */
	/* Here, we start by enabling the screen, then loading a GDT and IDT into the actual places they need to be. */
	
	/* Black the screen out. */
	screen_initialize();
	
	/* Prepare the serial line for our debug output. */
	init_serial();
	serial_print(0x3F8, "[INFO] Serial ready.\r\n");
	
	
	serial_print(0x3F8, "[INFO] Beginning GDT subroutine.\r\n");
	
	/* term_writes: writes a string to the terminal. */
	term_writes("GDT...");	
	
	/* Prepares the Global Descriptor Table, called from gdt.c */
	gdt_install();
	
	/* puts: writes a line to the terminal. */
	puts("GDT Ready.");
	serial_print(0x3F8, "[INFO] GDT subroutine complete.\r\n");
	
	/* Prepare the Interrupt Descriptor Table. */
	serial_print(0x3F8, "[INFO] Beginning IDT subroutine.\r\n");
	term_writes("IDT...");
	idt_install();
	puts("IDT Ready.");
	serial_print(0x3F8, "[INFO] IDT subroutine complete.\r\n[INFO] Enabling interrupts.\r\n");
	
	gdb_end(); /* The first important step. Waypoint it for gdb debugging. */
	
	term_writes("Memory available:");
	/* TODO: implement check_a20, which double-triple checks the state of the A20 line. */ 
	
	//if(check_a20())
		puts(" 4GB");
		serial_print(0x3F8, "[INFO] A20 enabled. 4GB memory available.");

	/* The first important thing: start the system clock immediately. */
	serial_print(0x3F8, "[INFO] Starting System Clock.\r\n");
	term_writes("Timer...");
	timer_install();
	puts("Timer Ready.");
	
	serial_print(0x3F8, "[INFO] All subsystems ready. Printing message.\r\n");
	
	/* Everything is ready; print a pretty message. */
	term_setcolor(RED);
	term_writes("\n(c)");
	term_setcolor(GREEN);
	term_writes(" Sync");
	term_setcolor(WHITE);
	term_writes(", 2019\n");
	
	serial_print(0x3F8, "[INFO] All operations complete. Checking for other tasks...\r\n");
	
	/* Here are a series of tests for the ANSI escape code and CSI implementations. */	
	term_writes("\x1b[BA"); /* Down a line, then A. */
	

	/* A stub causing a Divide by Zero error. */
	serial_print(0x3F8, "[DEBUG] Attempting a Divide by Zero error.\r\n");
	char div = (5 / 0);
	serial_print(0x3F8, "[DEBUG] Survived the error!\r\n");
	
	gdb_end(); /* Everything is done. The last debug routine. */
	return 0;
}