diff options
| -rw-r--r-- | .gitignore | 7 | ||||
| -rwxr-xr-x | build.sh | 31 | ||||
| -rwxr-xr-x | cross.sh | 13 | ||||
| -rw-r--r-- | src/boot.s | 41 | ||||
| -rw-r--r-- | src/grub.cfg | 3 | ||||
| -rw-r--r-- | src/kernel.c | 91 | ||||
| -rw-r--r-- | src/linker.ld | 35 |
7 files changed, 214 insertions, 7 deletions
@@ -1,3 +1,8 @@ .idea Melvix.iml -cross/
\ No newline at end of file + +build/ +cmake-build-debug/ +cross/ +cross64/ +iso/
\ No newline at end of file diff --git a/build.sh b/build.sh new file mode 100755 index 0000000..e0c6270 --- /dev/null +++ b/build.sh @@ -0,0 +1,31 @@ +#!/usr/bin/env sh +# Builds the operating system image + +# Install and source cross compiler if not already installed +. ./cross.sh + +# Create build directories +rm -rf ./build/ ./iso/ +mkdir ./build/ + +# Make source files +i686-elf-as ./src/boot.s -o ./build/boot.o +i686-elf-gcc -c ./src/kernel.c -o ./build/kernel.o -std=gnu99 -ffreestanding -O2 -Wall -Wextra +i686-elf-gcc -T ./src/linker.ld -o ./build/melvix.bin -ffreestanding -O2 -nostdlib ./build/boot.o ./build/kernel.o -lgcc + +# Testing +if grub-file --is-x86-multiboot ./build/melvix.bin; then + echo Multiboot confirmed +else + echo Melvix has errors and won\'t be able to multi boot! + exit +fi + +# Create ISO +mkdir -p ./iso/boot/grub +cp ./build/melvix.bin ./iso/boot/ +cp ./src/grub.cfg ./iso/boot/grub/ +grub-mkrescue -o ./build/melvix.iso ./iso/ + +# Run ISO +qemu-system-x86_64 -cdrom ./build/melvix.iso @@ -1,10 +1,11 @@ #!/usr/bin/env sh # Sets up a cross compiler +# TODO: Rewrite everything for 64-Bit -if [ ! -d "./cross64/" ]; then +if [ ! -d "./cross/" ]; then # Create directory - mkdir -p cross64 - cd cross64 || exit + mkdir -p cross + cd cross || exit DIR=$(pwd) # Get sources @@ -16,7 +17,7 @@ if [ ! -d "./cross64/" ]; then # Prepare compiling mkdir -p "${DIR}/opt/bin" export PREFIX="${DIR}/opt" - export TARGET=x86_64-elf + export TARGET=i686-elf export PATH="$PREFIX/bin:$PATH" # Compile binutilsq @@ -38,10 +39,10 @@ if [ ! -d "./cross64/" ]; then . cross.sh else # Should be sourced to take effect - cd cross64 || exit + cd cross || exit DIR=$(pwd) export PREFIX="${DIR}/opt" - export TARGET=x86_64-elf + export TARGET=i686-elf export PATH="$PREFIX/bin:$PATH" cd .. fi 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 |