120 lines
3.3 KiB
C
120 lines
3.3 KiB
C
/************************
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*** Team Kitty, 2019 ***
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*** Sync ***
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***********************/
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/* This file contains the entry point
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* to the kernel. This section consists
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* mainly of bootloading functions.
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*
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* Graphics and memory will be setup
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* at later stages.
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*/
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/* In the UEFI bootloading stages,
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* most of this setup is no longer
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* required.
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*
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* For example, a linear framebuffer
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* is provided at loading, so there is
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* no longer any need to initialise the
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* screen, or print using our functions.
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*
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* Additionally, there are some other
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* changes in how memory is mapped, but
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* since there are no memory functions
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* made yet, this is safe. 17/7/19
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*/
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//#include <stdio.h>
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#include <kernel.h>
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#include <kernel/tty.h>
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#include <kernel/serial.h>
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#include <kernel/descriptor_tables.h>
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void gdb_end() {} /* GDB Debugging stump */
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/* Because we are loading from UEFI, this
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* kernel entry point function is no longer
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* called.
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*
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* It will be left until its functionality has
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* been replicated into the UEFI entry point,
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* and then it will be removed.
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*
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*/
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int kernel_main(void) {
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/* The kernel is started in 32-bit protected mode by the ASM. */
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/* Here, we start by enabling the screen, then loading a GDT and IDT into the actual places they need to be. */
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/* Black the screen out. */
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screen_initialize();
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/* Prepare the serial line for our debug output. */
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init_serial();
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serial_print(0x3F8, "[INFO] Serial ready.\r\n");
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serial_print(0x3F8, "[INFO] Beginning GDT subroutine.\r\n");
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/* term_writes: writes a string to the terminal. */
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term_writes("GDT...");
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/* Prepares the Global Descriptor Table, called from gdt.c */
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gdt_install();
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/* puts: writes a line to the terminal. */
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puts("GDT Ready.");
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serial_print(0x3F8, "[INFO] GDT subroutine complete.\r\n");
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/* Prepare the Interrupt Descriptor Table. */
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serial_print(0x3F8, "[INFO] Beginning IDT subroutine.\r\n");
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term_writes("IDT...");
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idt_install();
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puts("IDT Ready.");
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serial_print(0x3F8, "[INFO] IDT subroutine complete.\r\n[INFO] Enabling interrupts.\r\n");
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gdb_end(); /* The first important step. Waypoint it for gdb debugging. */
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term_writes("Memory available:");
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/* TODO: implement check_a20, which double-triple checks the state of the A20 line. */
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//if(check_a20())
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puts(" 4GB");
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serial_print(0x3F8, "[INFO] A20 enabled. 4GB memory available.");
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/* The first important thing: start the system clock immediately. */
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serial_print(0x3F8, "[INFO] Starting System Clock.\r\n");
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term_writes("Timer...");
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timer_install();
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puts("Timer Ready.");
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serial_print(0x3F8, "[INFO] All subsystems ready. Printing message.\r\n");
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/* Everything is ready; print a pretty message. */
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term_setcolor(RED);
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term_writes("\n(c)");
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term_setcolor(GREEN);
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term_writes(" Sync");
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term_setcolor(WHITE);
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term_writes(", 2019\n");
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serial_print(0x3F8, "[INFO] All operations complete. Checking for other tasks...\r\n");
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/* Here are a series of tests for the ANSI escape code and CSI implementations. */
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term_writes("\x1b[BA"); /* Down a line, then A. */
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/* A stub causing a Divide by Zero error. */
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serial_print(0x3F8, "[DEBUG] Attempting a Divide by Zero error.\r\n");
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char div = (5 / 0);
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serial_print(0x3F8, "[DEBUG] Survived the error!\r\n");
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gdb_end(); /* Everything is done. The last debug routine. */
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return 0;
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}
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