4 files changed, 170 insertions, 0 deletions
diff --git a/src/boot.s b/src/boot.s
new file mode 100644
index 0000000..6cb2f7c
--- /dev/null
+++ b/src/boot.s
@@ -0,0 +1,41 @@
+// Constants for the multiboot header
+.set ALIGN, 1<<0
+.set MEMINFO, 1<<1
+.set FLAGS, ALIGN | MEMINFO
+.set MAGIC, 0x1BADB002
+.set CHECKSUM, -(MAGIC + FLAGS)
+
+// Header marking the program as kernel
+.section .multiboot
+.align 4
+.long MAGIC
+.long FLAGS
+.long CHECKSUM
+
+// Initialize a small stack
+.section .bss
+.align 16
+stack_bottom:
+.skip 16384 // 16 KiB
+stack_top:
+
+// Use _start from linker as starting point
+.section .text
+.global _start
+.type _start, @function
+_start:
+	// Set up stack by setting esp to top of stack
+	mov $stack_top, %esp
+
+	// TODO: Initialize processor, load GDT, enable paging
+
+	// Call the kernel
+	call kernel_main
+
+	// Put the system in an infinite loop
+	cli
+1:	hlt
+	jmp 1b
+
+// Set the size of the _start symbol to the current location '.' minus its start
+.size _start, . - _start
diff --git a/src/grub.cfg b/src/grub.cfg
new file mode 100644
index 0000000..c02de34
--- /dev/null
+++ b/src/grub.cfg
@@ -0,0 +1,3 @@
+menuentry "Melvix" {
+	multiboot /boot/melvix.bin
+}
+\ No newline at end of file
diff --git a/src/kernel.c b/src/kernel.c
new file mode 100644
index 0000000..a0c86ee
--- /dev/null
+++ b/src/kernel.c
@@ -0,0 +1,91 @@
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+// Hardware text mode color constants
+enum vga_color {
+    VGA_COLOR_BLACK = 0,
+    VGA_COLOR_BLUE = 1,
+    VGA_COLOR_GREEN = 2,
+    VGA_COLOR_CYAN = 3,
+    VGA_COLOR_RED = 4,
+    VGA_COLOR_MAGENTA = 5,
+    VGA_COLOR_BROWN = 6,
+    VGA_COLOR_LIGHT_GREY = 7,
+    VGA_COLOR_DARK_GREY = 8,
+    VGA_COLOR_LIGHT_BLUE = 9,
+    VGA_COLOR_LIGHT_GREEN = 10,
+    VGA_COLOR_LIGHT_CYAN = 11,
+    VGA_COLOR_LIGHT_RED = 12,
+    VGA_COLOR_LIGHT_MAGENTA = 13,
+    VGA_COLOR_LIGHT_BROWN = 14,
+    VGA_COLOR_WHITE = 15,
+};
+
+static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg) {
+    return fg | bg << 4;
+}
+
+static inline uint16_t vga_entry(unsigned char uc, uint8_t color) {
+    return (uint16_t) uc | (uint16_t) color << 8;
+}
+
+size_t strlen(const char *str) {
+    size_t len = 0;
+    while (str[len])
+        len++;
+    return len;
+}
+
+static const size_t VGA_WIDTH = 80;
+static const size_t VGA_HEIGHT = 25;
+
+size_t terminal_row;
+size_t terminal_column;
+uint8_t terminal_color;
+uint16_t *terminal_buffer;
+
+void terminal_initialize(void) {
+    terminal_row = 0;
+    terminal_column = 0;
+    terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
+    terminal_buffer = (uint16_t *) 0xB8000;
+    for (size_t y = 0; y < VGA_HEIGHT; y++) {
+        for (size_t x = 0; x < VGA_WIDTH; x++) {
+            const size_t index = y * VGA_WIDTH + x;
+            terminal_buffer[index] = vga_entry(' ', terminal_color);
+        }
+    }
+}
+
+void terminal_set_color(uint8_t color) {
+    terminal_color = color;
+}
+
+void terminal_put_entry_at(char c, uint8_t color, size_t x, size_t y) {
+    const size_t index = y * VGA_WIDTH + x;
+    terminal_buffer[index] = vga_entry(c, color);
+}
+
+void terminal_put_char(char c) {
+    terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
+    if (++terminal_column == VGA_WIDTH) {
+        terminal_column = 0;
+        if (++terminal_row == VGA_HEIGHT)
+            terminal_row = 0;
+    }
+}
+
+void terminal_write(const char *data, size_t size) {
+    for (size_t i = 0; i < size; i++)
+        terminal_putchar(data[i]);
+}
+
+void terminal_write(const char *data) {
+    terminal_write(data, strlen(data));
+}
+
+void kernel_main(void) {
+    terminal_initialize();
+    terminal_write("Melvix loaded successfully!");
+}
+\ No newline at end of file
diff --git a/src/linker.ld b/src/linker.ld
new file mode 100644
index 0000000..10315a5
--- /dev/null
+++ b/src/linker.ld
@@ -0,0 +1,35 @@
+/* Specify entry for bootloader */
+ENTRY(_start)
+ 
+/* Specify position of object files in kernel image */
+SECTIONS
+{
+	/* Start at 1MiB */
+	. = 1M;
+ 
+	/* First multiboot header then text section */
+	.text BLOCK(4K) : ALIGN(4K)
+	{
+		*(.multiboot)
+		*(.text)
+	}
+ 
+	/* Read-only data */
+	.rodata BLOCK(4K) : ALIGN(4K)
+	{
+		*(.rodata)
+	}
+ 
+	/* Read-write data (initialized) */
+	.data BLOCK(4K) : ALIGN(4K)
+	{
+		*(.data)
+	}
+ 
+	/* Read-write data (uninitialized) and stack */
+	.bss BLOCK(4K) : ALIGN(4K)
+	{
+		*(COMMON)
+		*(.bss)
+	}
+}
+\ No newline at end of file