commit 526b8472fe9bad12b6f433dcaedb0d595bf3a15f
Author: evenfri <evenfri256@gmail.com>
Date: Sun, 2 Aug 2026 01:57:00 +0800
initial commit
Diffstat:
31 files changed, 1731 insertions(+), 0 deletions(-)
diff --git a/.gitignore b/.gitignore
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+**/*.o
+**/o.*
+**/*.a
diff --git a/LICENSE b/LICENSE
@@ -0,0 +1,674 @@
+ GNU GENERAL PUBLIC LICENSE
+ Version 3, 29 June 2007
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+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) <year> <name of author>
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ <program> Copyright (C) <year> <name of author>
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/README b/README
@@ -0,0 +1,4 @@
+kernel
+======
+
+my hobby is writing an open source kernel with minimal use of AI
diff --git a/boot.s b/boot.s
@@ -0,0 +1,38 @@
+/* declare constants for the multiboot header. */
+.set ALIGN, 1<<0
+.set MEMINFO, 1<<1
+.set FLAGS, ALIGN | MEMINFO
+.set MAGIC, 0x1BADB002
+.set CHECKSUM, -(MAGIC + FLAGS)
+
+.section .multiboot
+.align 4
+.long MAGIC
+.long FLAGS
+.long CHECKSUM
+
+.section .bss
+.align 16
+stack_bottom:
+.skip 16384 /* 16 KiB */
+stack_top:
+
+.section .text
+.global _start
+.type _start, @function
+_start:
+ /* setup stack */
+ mov $stack_top, %esp
+
+ /* enter the high-level kernel */
+
+ push %ebx
+ push %eax
+
+ call start_kernel
+
+ cli
+1: hlt
+ jmp 1b
+
+.size _start, . - _start
diff --git a/build/ar b/build/ar
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+exec i686-elf-ar "$@"
diff --git a/build/as b/build/as
@@ -0,0 +1,16 @@
+#!/bin/sh
+s_file=""
+has_o=""
+
+for arg; do
+ case "$arg" in
+ -o|-o*) has_o=1 ;;
+ *.s|*.S) s_file="$arg" ;;
+ esac
+done
+
+if [ -n "$s_file" ] && [ -z "$has_o" ]; then
+ exec i686-elf-as "$@" -o "${s_file%.*}.o"
+fi
+
+exec i686-elf-as -c "$@"
diff --git a/build/cc b/build/cc
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+exec i686-elf-gcc -c \
+ -O0 \
+ -nostdlib \
+ -ffreestanding \
+ -fno-builtin \
+ -I. \
+ "$@"
diff --git a/build/ld b/build/ld
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+exec i686-elf-ld -T linker.ld \
+ -nostdlib \
+ -static \
+ -no-pie \
+ "$@"
diff --git a/build/mkcommon b/build/mkcommon
@@ -0,0 +1,23 @@
+%.$o: $hfiles # don't combine with following %.$o rules
+
+%.$o: %.c
+ $cc $cflags $stem.c
+
+%.$o: %.cc
+ $cc $cflags $stem.cc
+
+%.$o: %.s
+ $as $aflags $stem.s
+
+nuke:V: nuke-common
+clean:V: clean-common
+%.clean:V: %.clean-common
+
+nuke-common:V:
+ rm -f *.[$os] [$os].out $cleanfiles $nukefiles
+
+clean-common:
+ rm -f *.[$os] [$os].out $cleanfiles
+
+%.clean-common:V:
+ rm -f $stem.[$os] [$os].$stem $stem.acid $stem
diff --git a/build/mkdirs b/build/mkdirs
@@ -0,0 +1,10 @@
+dir-%:QV:
+ for i in $dirs
+ do
+ (cd $i; mk $mkflags $stem)
+ done
+
+all:V: dir-all
+clean:V: dir-clean
+install:V: dir-install
+nuke:V: dir-nuke
diff --git a/build/mkhdr b/build/mkhdr
@@ -0,0 +1,17 @@
+o=o
+os=$o
+a=a
+
+cc=cc
+ld=cc
+as=as
+ar=ar
+cflags=
+ldflags=
+aflags=
+cleanfiles=
+nukefiles=
+lib=
+shortlib=
+
+<|cat $LPLAN9/config 2>/dev/null || true
diff --git a/build/mklib b/build/mklib
@@ -0,0 +1,14 @@
+default:V: $lib
+
+$lib(%):N: %
+$lib: ${ofiles:%=$lib(%)}
+ $ar rsc $lib $newmember
+
+&:n: &.$o
+ $ar rsc $lib $stem.$o
+
+all install:V: $lib
+
+cleanfiles=$cleanfiles $lib
+
+<$LPLAN9/src/mkcommon
diff --git a/build/mkmany b/build/mkmany
@@ -0,0 +1,24 @@
+progs=${targ:%=$o.%}
+
+all:V: $progs
+
+$o.%: %.$o $ofiles $lib # ${shortlib:%=$libdir/lib%.a}
+ $ld -o $target $prereq $ldflags
+
+%.install:V: $bin/%
+
+$bin/%: $o.%
+ $install $o.$stem $bin/$stem
+
+many-install:V:
+ for i in $targ
+ do
+ mk $mkflags $i.install
+ done
+
+install:V: many-install
+
+cleanfiles=$cleanfiles $progs
+nukefiles=$nukefiles ${targ:%=$bin/%}
+
+<build/mkcommon
diff --git a/build/mkone b/build/mkone
@@ -0,0 +1,17 @@
+prog=$o.$targ
+
+all:V: $prog
+
+$prog: $ofiles $lib # ${shortlib:%=$libdir/lib%.a}
+ $ld -o $target $prereq $ldflags
+
+install:V: $targ.install
+%.install:V: $bin/%
+
+$bin/%: $o.%
+ $install $o.$stem $bin/$stem
+
+cleanfiles=$cleanfiles $prog
+nukefiles=$nukefiles $bin/$targ
+
+<build/mkcommon
diff --git a/dat.h b/dat.h
@@ -0,0 +1,61 @@
+#ifndef dat_h
+#define dat_h
+
+#include <stdint.h>
+#include <stddef.h>
+
+/* vga */
+#define vga_width 80
+#define vga_height 25
+#define vga_start 0xb8000
+#define vga_ctrl 0x3d4
+#define vga_data 0x3d5
+
+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,
+};
+
+/* idt */
+typedef struct {
+ uint16_t isr_low; /* the lower 16 bits of the isr's address */
+ uint16_t kernel_cs; /* the gdt segment selector that the cpu will load into cs before calling the isr */
+ uint8_t reserved; /* set to zero */
+ uint8_t attr; /* type and attributes; see the idt page */
+ uint16_t isr_high; /* the higher 16 bits of the isr's address */
+} __attribute__((packed)) idt_entry_t;
+
+typedef struct {
+ uint16_t limit;
+ uint32_t base;
+} __attribute__((packed)) idtr_t;
+
+typedef void (*int_handler)();
+
+#define icw_1 0x11
+
+#define pic_1 0x20
+#define pic_2 0xa0
+#define pic_1_comm pic_1
+#define pic_1_data (pic_1+1)
+#define pic_2_comm pic_2
+#define pic_2_data (pic_2+1)
+
+#define irq_0 0x20
+#define irq_8 0x28
+
+#endif /* dat_h */
diff --git a/fns.h b/fns.h
@@ -0,0 +1,57 @@
+#ifndef fns_h
+#define fns_h
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include <dat.h>
+
+/* input/output ports */
+static inline void io_wait() {
+ asm volatile ("outb %%al, $0x80" : : "a"(0));
+}
+
+static inline void outb(uint16_t port, uint8_t val) {
+ asm volatile ("outb %0, %1" : : "a"(val), "Nd"(port));
+}
+
+static inline uint8_t inb(uint16_t port) {
+ uint8_t ret;
+ asm volatile ("inb %1, %0" : "=a"(ret) : "Nd"(port));
+ return ret;
+}
+
+/* string */
+size_t strlen(const char* str);
+
+/* vga */
+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;
+}
+
+/* vga cursor */
+void vga_cursor_enable(uint8_t s, uint8_t e);
+void vga_cursor_disable(void);
+void vga_cursor_update(int x, int y);
+uint16_t vga_cursor_get_pos(void);
+
+/* gdt */
+extern void gdt_init(void);
+
+/* idt */
+void idt_register(unsigned char vec, int_handler handler);
+void idt_init(void);
+
+/* tty */
+void tty_init(void);
+void tty_set_color(uint8_t color);
+void tty_clear(void);
+void tty_putchar(char c);
+void tty_write(const char* data, size_t size);
+
+
+#endif /* fns_h */
diff --git a/gdt.s b/gdt.s
@@ -0,0 +1,39 @@
+.global gdt_init
+.section .data
+.align 4
+
+gdt_desc:
+ .word gdt_end - gdt - 1 # limit
+ .long gdt # start
+
+gdt:
+gdt_null:
+ .long 0x00000000
+ .long 0x00000000
+
+gdt_code:
+ .long 0x0000ffff
+ .long 0x00cf9a00
+
+gdt_data:
+ .long 0x0000ffff
+ .long 0x00cf9200
+
+gdt_end:
+
+.section .text
+
+gdt_init:
+ lgdt (gdt_desc)
+
+ movw $0x10, %ax
+ movw %ax, %ds
+ movw %ax, %es
+ movw %ax, %fs
+ movw %ax, %gs
+ movw %ax, %ss
+
+ ljmp $0x08, $.clean_pipe
+
+.clean_pipe:
+ ret
diff --git a/idt.c b/idt.c
@@ -0,0 +1,56 @@
+#include <fns.h>
+
+static idt_entry_t idt[256];
+static idtr_t idtr;
+
+void excp_handler() {
+ asm volatile ("cli; hlt");
+}
+
+void pic_remap() {
+ asm volatile ("cli");
+
+ outb(pic_1_comm, icw_1); io_wait();
+ outb(pic_2_comm, icw_1); io_wait();
+
+ outb(pic_1_data, irq_0); io_wait();
+ outb(pic_2_data, irq_8); io_wait();
+
+ outb(pic_1_data, 0x04); io_wait();
+ outb(pic_2_data, 0x02); io_wait();
+
+ outb(pic_1_data, 0x01); io_wait();
+ outb(pic_2_data, 0x01); io_wait();
+
+ outb(pic_1_data, 0b11111101); io_wait();
+ outb(pic_2_data, 0xff); io_wait();
+
+ asm volatile ("sti");
+}
+
+void idt_load() {
+ int idt_row_count = sizeof(idt) / sizeof(idt[0]);
+ idtr.base = (unsigned int)(&idt[0]);
+ idtr.limit = (sizeof(idt_entry_t) * idt_row_count) - 1;
+ asm volatile ("lidt %0" : : "m" (idtr));
+}
+
+void idt_register(unsigned char vec, int_handler handler) {
+ asm volatile ("cli");
+
+ unsigned int addr = (unsigned int) handler;
+
+ idt[vec].isr_low = addr & 0xffff;
+ idt[vec].kernel_cs = 0x08;
+ idt[vec].reserved = 0;
+ idt[vec].attr = 0x8e;
+ idt[vec].isr_high = addr >> 16;
+
+ idt_load();
+
+ asm volatile ("sti");
+}
+
+void idt_init(void) {
+ pic_remap();
+}
diff --git a/init.c b/init.c
@@ -0,0 +1,34 @@
+#include <stdint.h>
+#include <multiboot.h>
+#include <fns.h>
+#include <keyboard/keyboard.h>
+
+void multiboot(uint32_t magic, multiboot_info_t *mbi) {
+ if (magic != MULTIBOOT_BOOTLOADER_MAGIC) {
+ return;
+ }
+ (void)*mbi;
+}
+
+void start_kernel(uint32_t magic, multiboot_info_t *mbi){
+ multiboot(magic, mbi);
+
+ gdt_init();
+ idt_init();
+ keyboard_init();
+
+
+ tty_init();
+ tty_write("Hello world\n", 12);
+
+ while(1) {
+ asm volatile("sti");
+ char c = keyboard_read();
+
+ if (c) {
+ tty_putchar(c);
+ } else {
+ asm volatile("hlt");
+ }
+ }
+}
diff --git a/ints.s b/ints.s
@@ -0,0 +1,69 @@
+.macro isr_no_err_stub num
+.global isr_stub_\num
+
+isr_stub_\num:
+ pushl $0
+ pushl $\num
+ jmp isr_common_stub
+.endm
+
+.macro isr_err_stub num
+.global isr_stub_\num
+
+isr_stub_\num:
+ pushl $\num /* interrupt number */
+ jmp isr_common_stub
+.endm
+
+isr_common_stub:
+ pusha
+
+ movw %ds, %ax
+ pushl %eax
+
+ movw $0x10, %ax
+ movw %ax, %ds
+ movw %ax, %es
+
+ call excp_handler
+
+ popl %eax
+ movw %ax, %ds
+ movw %ax, %es
+
+ popa
+ addl $8, %esp
+ iret
+
+isr_no_err_stub 0
+isr_no_err_stub 1
+isr_no_err_stub 2
+isr_no_err_stub 3
+isr_no_err_stub 4
+isr_no_err_stub 5
+isr_no_err_stub 6
+isr_no_err_stub 7
+isr_err_stub 8
+isr_no_err_stub 9
+isr_err_stub 10
+isr_err_stub 11
+isr_err_stub 12
+isr_err_stub 13
+isr_err_stub 14
+isr_no_err_stub 15
+isr_no_err_stub 16
+isr_err_stub 17
+isr_no_err_stub 18
+isr_no_err_stub 19
+isr_no_err_stub 20
+isr_no_err_stub 21
+isr_no_err_stub 22
+isr_no_err_stub 23
+isr_no_err_stub 24
+isr_no_err_stub 25
+isr_no_err_stub 26
+isr_no_err_stub 27
+isr_no_err_stub 28
+isr_no_err_stub 29
+isr_err_stub 30
+isr_no_err_stub 31
diff --git a/keyboard/keyboard.c b/keyboard/keyboard.c
@@ -0,0 +1,74 @@
+#include <fns.h>
+#include "keyboard.h"
+
+unsigned int shift_state = 0;;
+
+unsigned char buf[buf_size];
+unsigned int buf_head = 0;
+unsigned int buf_tail = 0;
+
+const char lower_scancodes[128] = {
+ 0, 0, '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '-',
+ '=', '\b', '\t', 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p',
+ '[', ']', '\n', 0, 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l',
+ ';', '\'', '`', 0, '\\', 'z', 'x', 'c', 'v', 'b', 'n', 'm', ',',
+ '.', '/', 0, '*', 0, ' ', 0, 0, 0, 0, 0, 0};
+
+const char upper_scancodes[128] = {
+ 0, 0, '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '_',
+ '+', '\b', '\t', 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p',
+ '{', '}', '\n', 0, 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l',
+ ':', '\"', '~', 0, '|', 'z', 'x', 'c', 'v', 'b', 'n', 'm', '<',
+ '>', '?', 0, '*', 0, ' ', 0, 0, 0, 0, 0, 0};
+
+extern void keyboard_asm(void);
+
+char keyboard_read(void) {
+ while (buf_head == buf_tail) {
+ asm volatile("hlt");
+ }
+
+ char ch = buf[buf_head];
+
+ buf_head = (buf_head + 1) % buf_size;
+
+ return ch;
+}
+
+void keyboard_handler(void) {
+ unsigned char scancode = inb(0x60);
+
+ if (scancode == 0x2a || scancode == 0x36) {
+ shift_state = 1;
+ outb(0x20, 0x20);
+ return;
+ } else if (scancode == 0xaa || scancode == 0xb6) {
+ shift_state = 0;
+ outb(0x20, 0x20);
+ return;
+ }
+
+ if (scancode < 0x80) {
+ char ascii_char;
+
+ if (shift_state) {
+ ascii_char = upper_scancodes[scancode];
+ } else {
+ ascii_char = lower_scancodes[scancode];
+ }
+
+ if (ascii_char != 0) {
+ unsigned int next_tail = (buf_tail + 1) % buf_size;
+ if (next_tail != buf_head) {
+ buf[buf_tail] = ascii_char;
+ buf_tail = next_tail;
+ }
+ }
+ }
+
+ outb(0x20, 0x20);
+}
+
+void keyboard_init() {
+ idt_register(33, keyboard_asm);
+}
diff --git a/keyboard/keyboard.h b/keyboard/keyboard.h
@@ -0,0 +1,9 @@
+#ifndef keyboard_h
+#define keyboard_h
+
+#define buf_size 16
+
+char keyboard_read(void);
+void keyboard_init(void);
+
+#endif /* keyboard_h */
diff --git a/keyboard/keyboard_as.s b/keyboard/keyboard_as.s
@@ -0,0 +1,8 @@
+.global keyboard_asm
+.extern keyboard_handler
+
+keyboard_asm:
+ pusha
+ call keyboard_handler
+ popa
+ iret
diff --git a/keyboard/mkfile b/keyboard/mkfile
@@ -0,0 +1,17 @@
+<../build/mkhdr
+
+as = ../build/as
+cc = ../build/cc
+ar = ../build/ar
+
+cflags = -I..
+
+ofiles = keyboard_as.$o \
+ keyboard.$o
+
+hfiles = keyboard.h
+
+lib = built-in.a
+
+<../build/mkcommon
+<../build/mklib
diff --git a/linker.ld b/linker.ld
@@ -0,0 +1,26 @@
+ENTRY(_start)
+
+SECTIONS {
+ . = 1M;
+
+ .text BLOCK(4K) : ALIGN(4K) {
+ *(.multiboot)
+ *(.text)
+ }
+
+ /* ro data */
+ .rodata BLOCK(4K) : ALIGN(4K) {
+ *(.rodata)
+ }
+
+ /* rw data */
+ .data BLOCK(4K) : ALIGN(4K) {
+ *(.data)
+ }
+
+ /* rw data and stack */
+ .bss BLOCK(4K) : ALIGN(4K) {
+ *(COMMON)
+ *(.bss)
+ }
+}
diff --git a/mkfile b/mkfile
@@ -0,0 +1,26 @@
+<build/mkhdr
+<build/mkdirs
+
+as = ./build/as
+cc = ./build/cc
+ld = ./build/ld
+ar = ./build/ar
+
+ldflags = keyboard/built-in.a
+dirs = keyboard
+
+ofiles = boot.$o \
+ vga.$o \
+ gdt.$o \
+ idt.$o \
+ ints.$o \
+ tty.$o \
+ init.$o \
+ strlen.$o
+
+hfiles = fns.h \
+ dat.h
+
+targ = kernel
+
+<build/mkone
diff --git a/multiboot.h b/multiboot.h
@@ -0,0 +1,274 @@
+/* multiboot.h - Multiboot header file. */
+/* Copyright (C) 1999,2003,2007,2008,2009,2010 Free Software Foundation, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL ANY
+ * DEVELOPER OR DISTRIBUTOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+ * IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef MULTIBOOT_HEADER
+#define MULTIBOOT_HEADER 1
+
+/* How many bytes from the start of the file we search for the header. */
+#define MULTIBOOT_SEARCH 8192
+#define MULTIBOOT_HEADER_ALIGN 4
+
+/* The magic field should contain this. */
+#define MULTIBOOT_HEADER_MAGIC 0x1BADB002
+
+/* This should be in %eax. */
+#define MULTIBOOT_BOOTLOADER_MAGIC 0x2BADB002
+
+/* Alignment of multiboot modules. */
+#define MULTIBOOT_MOD_ALIGN 0x00001000
+
+/* Alignment of the multiboot info structure. */
+#define MULTIBOOT_INFO_ALIGN 0x00000004
+
+/* Flags set in the ’flags’ member of the multiboot header. */
+
+/* Align all boot modules on i386 page (4KB) boundaries. */
+#define MULTIBOOT_PAGE_ALIGN 0x00000001
+
+/* Must pass memory information to OS. */
+#define MULTIBOOT_MEMORY_INFO 0x00000002
+
+/* Must pass video information to OS. */
+#define MULTIBOOT_VIDEO_MODE 0x00000004
+
+/* This flag indicates the use of the address fields in the header. */
+#define MULTIBOOT_AOUT_KLUDGE 0x00010000
+
+/* Flags to be set in the ’flags’ member of the multiboot info structure. */
+
+/* is there basic lower/upper memory information? */
+#define MULTIBOOT_INFO_MEMORY 0x00000001
+/* is there a boot device set? */
+#define MULTIBOOT_INFO_BOOTDEV 0x00000002
+/* is the command-line defined? */
+#define MULTIBOOT_INFO_CMDLINE 0x00000004
+/* are there modules to do something with? */
+#define MULTIBOOT_INFO_MODS 0x00000008
+
+/* These next two are mutually exclusive */
+
+/* is there a symbol table loaded? */
+#define MULTIBOOT_INFO_AOUT_SYMS 0x00000010
+/* is there an ELF section header table? */
+#define MULTIBOOT_INFO_ELF_SHDR 0X00000020
+
+/* is there a full memory map? */
+#define MULTIBOOT_INFO_MEM_MAP 0x00000040
+
+/* Is there drive info? */
+#define MULTIBOOT_INFO_DRIVE_INFO 0x00000080
+
+/* Is there a config table? */
+#define MULTIBOOT_INFO_CONFIG_TABLE 0x00000100
+
+/* Is there a boot loader name? */
+#define MULTIBOOT_INFO_BOOT_LOADER_NAME 0x00000200
+
+/* Is there a APM table? */
+#define MULTIBOOT_INFO_APM_TABLE 0x00000400
+
+/* Is there video information? */
+#define MULTIBOOT_INFO_VBE_INFO 0x00000800
+#define MULTIBOOT_INFO_FRAMEBUFFER_INFO 0x00001000
+
+#ifndef ASM_FILE
+
+typedef unsigned char multiboot_uint8_t;
+typedef unsigned short multiboot_uint16_t;
+typedef unsigned int multiboot_uint32_t;
+typedef unsigned long long multiboot_uint64_t;
+
+struct multiboot_header
+{
+ /* Must be MULTIBOOT_MAGIC - see above. */
+ multiboot_uint32_t magic;
+
+ /* Feature flags. */
+ multiboot_uint32_t flags;
+
+ /* The above fields plus this one must equal 0 mod 2^32. */
+ multiboot_uint32_t checksum;
+
+ /* These are only valid if MULTIBOOT_AOUT_KLUDGE is set. */
+ multiboot_uint32_t header_addr;
+ multiboot_uint32_t load_addr;
+ multiboot_uint32_t load_end_addr;
+ multiboot_uint32_t bss_end_addr;
+ multiboot_uint32_t entry_addr;
+
+ /* These are only valid if MULTIBOOT_VIDEO_MODE is set. */
+ multiboot_uint32_t mode_type;
+ multiboot_uint32_t width;
+ multiboot_uint32_t height;
+ multiboot_uint32_t depth;
+};
+
+/* The symbol table for a.out. */
+struct multiboot_aout_symbol_table
+{
+ multiboot_uint32_t tabsize;
+ multiboot_uint32_t strsize;
+ multiboot_uint32_t addr;
+ multiboot_uint32_t reserved;
+};
+typedef struct multiboot_aout_symbol_table multiboot_aout_symbol_table_t;
+
+/* The section header table for ELF. */
+struct multiboot_elf_section_header_table
+{
+ multiboot_uint32_t num;
+ multiboot_uint32_t size;
+ multiboot_uint32_t addr;
+ multiboot_uint32_t shndx;
+};
+typedef struct multiboot_elf_section_header_table multiboot_elf_section_header_table_t;
+
+struct multiboot_info
+{
+ /* Multiboot info version number */
+ multiboot_uint32_t flags;
+
+ /* Available memory from BIOS */
+ multiboot_uint32_t mem_lower;
+ multiboot_uint32_t mem_upper;
+
+ /* "root" partition */
+ multiboot_uint32_t boot_device;
+
+ /* Kernel command line */
+ multiboot_uint32_t cmdline;
+
+ /* Boot-Module list */
+ multiboot_uint32_t mods_count;
+ multiboot_uint32_t mods_addr;
+
+ union
+ {
+ multiboot_aout_symbol_table_t aout_sym;
+ multiboot_elf_section_header_table_t elf_sec;
+ } u;
+
+ /* Memory Mapping buffer */
+ multiboot_uint32_t mmap_length;
+ multiboot_uint32_t mmap_addr;
+
+ /* Drive Info buffer */
+ multiboot_uint32_t drives_length;
+ multiboot_uint32_t drives_addr;
+
+ /* ROM configuration table */
+ multiboot_uint32_t config_table;
+
+ /* Boot Loader Name */
+ multiboot_uint32_t boot_loader_name;
+
+ /* APM table */
+ multiboot_uint32_t apm_table;
+
+ /* Video */
+ multiboot_uint32_t vbe_control_info;
+ multiboot_uint32_t vbe_mode_info;
+ multiboot_uint16_t vbe_mode;
+ multiboot_uint16_t vbe_interface_seg;
+ multiboot_uint16_t vbe_interface_off;
+ multiboot_uint16_t vbe_interface_len;
+
+ multiboot_uint64_t framebuffer_addr;
+ multiboot_uint32_t framebuffer_pitch;
+ multiboot_uint32_t framebuffer_width;
+ multiboot_uint32_t framebuffer_height;
+ multiboot_uint8_t framebuffer_bpp;
+#define MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED 0
+#define MULTIBOOT_FRAMEBUFFER_TYPE_RGB 1
+#define MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT 2
+ multiboot_uint8_t framebuffer_type;
+ union
+ {
+ struct
+ {
+ multiboot_uint32_t framebuffer_palette_addr;
+ multiboot_uint16_t framebuffer_palette_num_colors;
+ };
+ struct
+ {
+ multiboot_uint8_t framebuffer_red_field_position;
+ multiboot_uint8_t framebuffer_red_mask_size;
+ multiboot_uint8_t framebuffer_green_field_position;
+ multiboot_uint8_t framebuffer_green_mask_size;
+ multiboot_uint8_t framebuffer_blue_field_position;
+ multiboot_uint8_t framebuffer_blue_mask_size;
+ };
+ };
+};
+typedef struct multiboot_info multiboot_info_t;
+
+struct multiboot_color
+{
+ multiboot_uint8_t red;
+ multiboot_uint8_t green;
+ multiboot_uint8_t blue;
+};
+
+struct multiboot_mmap_entry
+{
+ multiboot_uint32_t size;
+ multiboot_uint64_t addr;
+ multiboot_uint64_t len;
+#define MULTIBOOT_MEMORY_AVAILABLE 1
+#define MULTIBOOT_MEMORY_RESERVED 2
+#define MULTIBOOT_MEMORY_ACPI_RECLAIMABLE 3
+#define MULTIBOOT_MEMORY_NVS 4
+#define MULTIBOOT_MEMORY_BADRAM 5
+ multiboot_uint32_t type;
+} __attribute__((packed));
+typedef struct multiboot_mmap_entry multiboot_memory_map_t;
+
+struct multiboot_mod_list
+{
+ /* the memory used goes from bytes ’mod_start’ to ’mod_end-1’ inclusive */
+ multiboot_uint32_t mod_start;
+ multiboot_uint32_t mod_end;
+
+ /* Module command line */
+ multiboot_uint32_t cmdline;
+
+ /* padding to take it to 16 bytes (must be zero) */
+ multiboot_uint32_t pad;
+};
+typedef struct multiboot_mod_list multiboot_module_t;
+
+/* APM BIOS info. */
+struct multiboot_apm_info
+{
+ multiboot_uint16_t version;
+ multiboot_uint16_t cseg;
+ multiboot_uint32_t offset;
+ multiboot_uint16_t cseg_16;
+ multiboot_uint16_t dseg;
+ multiboot_uint16_t flags;
+ multiboot_uint16_t cseg_len;
+ multiboot_uint16_t cseg_16_len;
+ multiboot_uint16_t dseg_len;
+};
+
+#endif /* ! ASM_FILE */
+
+#endif /* ! MULTIBOOT_HEADER */
diff --git a/qemu.sh b/qemu.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+set -e
+kernel_bin="o.kernel"
+
+qemu-system-i386 -kernel "$kernel_bin"
+
diff --git a/strlen.c b/strlen.c
@@ -0,0 +1,8 @@
+#include <fns.h>
+
+size_t strlen(const char* str) {
+ size_t len = 0;
+ while (str[len])
+ len++;
+ return len;
+}
diff --git a/tty.c b/tty.c
@@ -0,0 +1,70 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <dat.h>
+#include <fns.h>
+
+size_t tty_row;
+size_t tty_column;
+uint8_t tty_color;
+uint16_t* tty_buffer = (uint16_t*)vga_start;
+
+void tty_set_color(uint8_t color) {
+ tty_color = color;
+}
+
+void tty_putentryat(char c, uint8_t color, size_t x, size_t y) {
+ const size_t index = y * vga_width + x;
+ tty_buffer[index] = vga_entry(c, color);
+}
+
+void tty_clear(void) {
+ tty_row = 0;
+ tty_column = 0;
+
+ 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;
+ tty_buffer[index] = vga_entry(' ', tty_color);
+ }
+ }
+ vga_cursor_update(tty_column, tty_row);
+}
+
+void tty_init(void) {
+ vga_cursor_enable(14, 15);
+ tty_color = vga_entry_color(vga_color_light_grey, vga_color_black);
+ tty_clear();
+}
+
+void tty_putchar(char c) {
+ if(c == '\n') {
+ tty_row++;
+ tty_column = 0;
+
+ if (tty_row >= vga_height) {
+ tty_row = 0;
+ }
+ } else if(c == '\b') {
+ if (tty_column > 0) {
+ tty_column--;
+ tty_putentryat(' ', tty_color, tty_column, tty_row);
+ }
+ } else {
+ tty_putentryat(c, tty_color, tty_column, tty_row);
+ if (++tty_column == vga_width) {
+ tty_column = 0;
+ if (++tty_row == vga_height) {
+ tty_row = 0;
+ }
+ }
+ }
+
+ vga_cursor_update(tty_column, tty_row);
+}
+
+void tty_write(const char* data, size_t size) {
+ for(size_t i = 0; i < size; i++) {
+ tty_putchar(data[i]);
+ }
+}
+
diff --git a/vga.c b/vga.c
@@ -0,0 +1,37 @@
+#include <stdint.h>
+#include <dat.h>
+#include <fns.h>
+
+void vga_cursor_enable(uint8_t s, uint8_t e) {
+ outb(vga_ctrl, 0x0a);
+ outb(vga_data, (inb(vga_data) & 0xc0) | s);
+
+ outb(vga_ctrl, 0x0b);
+ outb(vga_data, (inb(vga_data) & 0xe0) | e);
+}
+
+void vga_cursor_disable(void) {
+ outb(vga_ctrl, 0x0a);
+ outb(vga_data, 0x20);
+}
+
+void vga_cursor_update(int x, int y) {
+ uint16_t pos = y * vga_width + x;
+ outb(vga_ctrl, 0x0f);
+ outb(vga_data, (uint8_t) (pos & 0xff));
+
+ outb(vga_ctrl, 0x0e);
+ outb(vga_data, (uint8_t) ((pos >> 8) & 0xff));
+}
+
+uint16_t vga_cursor_get_pos(void) {
+ uint16_t pos = 0;
+ outb(vga_ctrl, 0x0f);
+
+ pos |= inb(0x3d5);
+ outb(vga_ctrl, 0x0e);
+
+ pos |= ((uint16_t)inb(0x3d5) << 8);
+ return pos;
+}
+
