diff options
| -rw-r--r-- | .gitignore | 2 | ||||
| -rw-r--r-- | Makefile | 28 | ||||
| -rw-r--r-- | compile_flags.txt | 1 | ||||
| -rw-r--r-- | kernel/main.c | 7 | ||||
| -rw-r--r-- | kernel/tty.c | 32 | ||||
| -rw-r--r-- | kernel/tty.h | 6 | ||||
| -rw-r--r-- | linker.ld | 24 | ||||
| -rw-r--r-- | platform/boot.s | 32 |
8 files changed, 132 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..98f5968 --- /dev/null +++ b/.gitignore @@ -0,0 +1,2 @@ +*.bin +*.o diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..593ead0 --- /dev/null +++ b/Makefile @@ -0,0 +1,28 @@ +AS = i686-elf-as +CC = i686-elf-gcc +CFLAGS = -std=gnu99 -ffreestanding -O2 -Wall -Wextra +CFLAGS += -I. +LFLAGS = -ffreestanding -O2 -nostdlib -lgcc + +OBJ = platform/boot.o +OBJ += $(patsubst %.c,%.o,$(wildcard kernel/*.c)) + + +.PHONY: boot clean +boot: kernel.bin + qemu-system-i386 -kernel kernel.bin + +clean: + rm -vf kernel.bin + rm -vf **/*.o + + +kernel.bin: $(OBJ) + $(CC) $(LFLAGS) -T linker.ld $^ -o $@ + grub-file --is-x86-multiboot $@ + +platform/boot.o: platform/boot.s + $(AS) $^ -o $@ + +%.o: %.c + $(CC) $(CFLAGS) -c $^ -o $@ diff --git a/compile_flags.txt b/compile_flags.txt new file mode 100644 index 0000000..60a4aad --- /dev/null +++ b/compile_flags.txt @@ -0,0 +1 @@ +-I. diff --git a/kernel/main.c b/kernel/main.c new file mode 100644 index 0000000..73c66e2 --- /dev/null +++ b/kernel/main.c @@ -0,0 +1,7 @@ +#include <kernel/tty.h> + +void kmain() +{ + for (int i = 0; i < 400; i++) + tty_write("words ", 6); +} diff --git a/kernel/tty.c b/kernel/tty.c new file mode 100644 index 0000000..45de728 --- /dev/null +++ b/kernel/tty.c @@ -0,0 +1,32 @@ +/* will be moved to userspace later on */ + +#include <kernel/tty.h> + +struct vga_cell { + unsigned char c; + unsigned char style; +} __attribute__((__packed__)); + +static const size_t vga_len = 80 * 25; +static struct vga_cell *vga = (void*) 0xB8000; +static size_t vga_pos = 0; + +static void tty_scroll() { + for (int i = 0; i < vga_len - 80; i++) { + vga[i] = vga[i + 80]; + } + vga_pos -= 80; +} + +void tty_putchar(char c) +{ + if (vga_pos >= vga_len - 80) tty_scroll(); + vga[vga_pos++].c = c; +} + +void tty_write(const char *buf, size_t len) +{ + for (size_t i = 0; i < len; i++) { + tty_putchar(buf[i]); + } +} diff --git a/kernel/tty.h b/kernel/tty.h new file mode 100644 index 0000000..87a4744 --- /dev/null +++ b/kernel/tty.h @@ -0,0 +1,6 @@ +#pragma once + +#include <stddef.h> + +void tty_putchar(char c); +void tty_write(const char *buf, size_t len); diff --git a/linker.ld b/linker.ld new file mode 100644 index 0000000..dd7c64c --- /dev/null +++ b/linker.ld @@ -0,0 +1,24 @@ +ENTRY(_start) + +SECTIONS +{ + . = 1M; + .text BLOCK(4K) : ALIGN(4K) + { + *(.multiboot) + *(.text) + } + .rodata BLOCK(4K) : ALIGN(4K) + { + *(.rodata) + } + .data BLOCK(4K) : ALIGN(4K) + { + *(.data) + } + .bss BLOCK(4K) : ALIGN(4K) + { + *(COMMON) + *(.bss) + } +} diff --git a/platform/boot.s b/platform/boot.s new file mode 100644 index 0000000..77af2bc --- /dev/null +++ b/platform/boot.s @@ -0,0 +1,32 @@ +.set MAGIC, 0x1BADB002 +.set FLAG_ALIGN, 1<<0 /* align modules on page boundaries */ +.set FLAG_MEMINFO, 1<<1 /* memory map */ +.set FLAGS, FLAG_ALIGN | FLAG_MEMINFO +.set CHECKSUM, -(MAGIC + FLAGS) + +.section .multiboot +.align 4 +.long MAGIC +.long FLAGS +.long CHECKSUM + +/* a lil stack */ +.section .bss +.align 16 +stack_bottom: +.skip 16384 +stack_top: + + +.section .text +.global _start +.type _start, @function +_start: + mov $stack_top, %esp + call kmain + + cli /* disable interrupts */ +1: hlt + jmp 1b + +.size _start, . - _start |