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351
LICENSE
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@ -1,351 +0,0 @@
NOTICE! This version of the GPL is the only version which applies to
BRaDOS. Any former or later version does not apply unless explicitly stated
elsewhere!
Also, this license does not apply to software which runs under and/or makes
system calls to BRaDOS.
-L. Bradley LaBoon
-----------------------------------------------------------------------------
GNU GENERAL PUBLIC LICENSE
Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
Preamble
The licenses for most software are designed to take away your
freedom to share and change it. By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users. This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it. (Some other Free Software Foundation software is covered by
the GNU Lesser General Public License instead.) You can apply it to
your programs, too.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it
in new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid
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These restrictions translate to certain responsibilities for you if you
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For example, if you distribute copies of such a program, whether
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you have. You must make sure that they, too, receive or can get the
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We protect your rights with two steps: (1) copyright the software, and
(2) offer you this license which gives you legal permission to copy,
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Finally, any free program is threatened constantly by software
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The precise terms and conditions for copying, distribution and
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GNU GENERAL PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License applies to any program or other work which contains
a notice placed by the copyright holder saying it may be distributed
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and give any other recipients of the Program a copy of this License
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notice that there is no warranty (or else, saying that you provide
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the Program is not required to print an announcement.)
These requirements apply to the modified work as a whole. If
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implemented by public license practices. Many people have made
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This section is intended to make thoroughly clear what is believed to
be a consequence of the rest of this License.
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certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
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NO WARRANTY
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FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
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WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
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YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
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POSSIBILITY OF SUCH DAMAGES.
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
convey 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 2 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, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
Also add information on how to contact you by electronic and paper mail.
If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) year name of author
Gnomovision 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, the commands you use may
be called something other than `show w' and `show c'; they could even be
mouse-clicks or menu items--whatever suits your program.
You should also get your employer (if you work as a programmer) or your
school, if any, to sign a "copyright disclaimer" for the program, if
necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.
<signature of Ty Coon>, 1 April 1989
Ty Coon, President of Vice
This 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.

34
Makefile
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# Build environment
PREFIX ?= /usr/local/cross
ARCH ?= i586-elf
GNU ?= $(PREFIX)/$(ARCH)/bin/$(ARCH)
# Source files
SOURCES_ASM := arch/$(ARCH)/boot.s
SOURCES_C := arch/$(ARCH)/multiboot.c driver/video/vga.c kernel/brados.c kernel/printk.c lib/string.c
# Object files
OBJS := $(patsubst %.s,%.o,$(SOURCES_ASM))
OBJS += $(patsubst %.c,%.o,$(SOURCES_C))
# Build flags
CFLAGS = -std=gnu99 -ffreestanding -Iinclude/ -O2 -Wall -Wextra
LDFLAGS = -ffreestanding -O2 -nostdlib
# Build rules
all: brados.bin
.PHONY: all clean
brados.bin: $(OBJS) arch/$(ARCH)/linker.ld
$(GNU)-gcc -T arch/$(ARCH)/linker.ld -o $@ $(LDFLAGS) $(OBJS) -lgcc
clean:
rm -f $(OBJS) brados.bin
# C
%.o: %.c Makefile
$(GNU)-gcc -c $< -o $@ $(CFLAGS)
# Assembly
%.o: %.s Makefile
$(GNU)-as $< -o $@

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README
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@ -1,9 +1,5 @@
Welcome to BRaDOS! Welcome to BRaDOS!
BRaDOS is my personal OS project which I will be working on as I feel like it. BRaDOS is my personal OS project which I will be working on as I feel like it.
The main purpose of the project is for me to learn about OS developement. The main purpose of the project is for me to learn about OS developement, as
it's something I am interested in.
For the most part, this project will do things the way Linux does things, with
changes as I see fit. While I will make every attempt to ensure that the master
git branch only contains compilable code, I make no guarantees. Use of this OS
is entirely at your own risk.

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arch/arm-none-eabi/boot.s
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.section ".text.boot"
.globl Start
Start:
// Setup the stack
mov sp, #0x8000
// Clear out bss
ldr r4, =_bss_start
ldr r9, =_bss_end
mov r5, #0
mov r6, #0
mov r7, #0
mov r8, #0
b 2f
1:
// Store multiple at r4
stmia r4!, {r5-r8}
2:
// If we are still below bss_end, loop
cmp r4, r9
blo 1b
// Call brados_main
ldr r3, =brados_main
blx r3
halt:
// Halt
wfe
b halt

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arch/arm-none-eabi/linker.ld
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ENTRY(Start)
SECTIONS
{
/* Starts at LOADER_ADDR */
. = 0x8000;
_start = .;
_text_start = .;
.text :
{
KEEP(*(.text.boot))
*(.text)
}
. = ALIGN(4096);
_text_end = .;
_rodata_start = .;
.rodata :
{
*(.rodata)
}
. = ALIGN(4096);
_rodata_end = .;
_data_start = .;
.data :
{
*(.data)
}
. = ALIGN(4096);
_data_end = .;
_bss_start = .;
.bss :
{
bss = .;
*(.bss)
}
. = ALIGN(4096);
_bss_end = .;
_end = .;
}

13
arch/arm-none-eabi/multiboot.c
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#include <stdint.h>
#include <multiboot.h>
uint32_t multiboot_getAddress()
{
return 0;
}
uint32_t multiboot_getMagic()
{
return 0;
}

23
arch/i586-elf/multiboot.c
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@ -1,23 +0,0 @@
#include <stdint.h>
#include <multiboot.h>
uint32_t multiboot_getAddress()
{
uint32_t address = 0;
__asm__(
"movl %%ebx, %0;"
:"=r"(address)
);
return address;
}
uint32_t multiboot_getMagic()
{
uint32_t magic = 0;
__asm__(
"movl %%eax, %0;"
:"=r"(magic)
);
return magic;
}

83
arch/i586-elf/boot.s → boot/boot.s
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@ -1,43 +1,40 @@
# Declare constants for creating a multiboot header # Declare constants for creating a multiboot header
.set ALIGN, 1<<0 .set ALIGN, 1<<0
.set MEMINFO, 1<<1 .set MEMINFO, 1<<1
.set FLAGS, ALIGN | MEMINFO .set FLAGS, ALIGN | MEMINFO
.set MAGIC, 0x1BADB002 .set MAGIC, 0x1BADB002
.set CHECKSUM, -(MAGIC + FLAGS) .set CHECKSUM, -(MAGIC + FLAGS)
# Declare multiboot header # Declare multiboot header
.section .multiboot .section .multiboot
.align 4 .align 4
.long MAGIC .long MAGIC
.long FLAGS .long FLAGS
.long CHECKSUM .long CHECKSUM
# Create a 16 KiB stack # Create a 16 KiB stack
.section .bootstrap_stack .section .bootstrap_stack
stack_bottom: stack_bottom:
.skip 16384 .skip 16384
stack_top: stack_top:
# Kernel entry point # Kernel entry point
.section .text .section .text
.global _start .global _start
.type _start, @function .type _start, @function
_start: _start:
# We are now in kernel mode! # We are now in kernel mode!
# Setup the stack # Setup the stack
movl $stack_top, %esp movl $stack_top, %esp
# Push the multiboot information onto the stack # Call the main kernel function
push %ebx call brados_main
push %eax
# Call the main kernel function # In case the function returns, enter an endless loop
call brados_main cli
hlt
# In case the function returns, enter an endless loop .Lhang:
cli jmp .Lhang
hlt
.Lhang: # Set the size of the _start symbol for debugging
jmp .Lhang .size _start, . - _start
# Set the size of the _start symbol for debugging
.size _start, . - _start

111
driver/video/vga.c
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#include <stddef.h>
#include <stdint.h>
#include <brados/string.h>
#include <video/vga.h>
// Create a VGA color
uint8_t make_color(enum vga_color fg, enum vga_color bg)
{
return fg | bg << 4;
}
// Create a VGA character
uint16_t make_vgaEntry(char c, uint8_t color)
{
uint16_t c16 = c;
uint16_t color16 = color;
return c16 | color16 << 8;
}
// Initialize a VGA term
void term_init(struct vgastate *state)
{
state->term_row = state->term_col = 0;
state->term_color = make_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
state->term_buf = (uint16_t *) VGA_BUF;
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;
state->term_buf[index] = make_vgaEntry(' ', state->term_color);
}
}
}
// Write a character to a VGA term
void term_putChar(struct vgastate *state, char c)
{
if (c == '\n')
state->term_col = VGA_WIDTH - 1;
else
term_putEntryAt(state, c, state->term_color, state->term_col, state->term_row);
if (++state->term_col == VGA_WIDTH) {
state->term_col = 0;
if (++state->term_row == VGA_HEIGHT) {
state->term_row--;
term_scroll(state);
}
}
}
// Place a character in a VGA term's buffer
void term_putEntryAt(struct vgastate *state, char c, uint8_t color, size_t x, size_t y)
{
const size_t index = y * VGA_WIDTH + x;
state->term_buf[index] = make_vgaEntry(c, color);
}
// Scroll the term down 1 line
void term_scroll(struct vgastate *state)
{
// Move each row up
for (size_t y = 1; y < VGA_HEIGHT; y++) {
for (size_t x = 0; x < VGA_WIDTH; x++) {
const size_t index = y * VGA_WIDTH + x;
const size_t indexBelow = (y - 1) * VGA_WIDTH + x;
state->term_buf[indexBelow] = state->term_buf[index];
}
}
// Clear the last line
for (size_t x = 0; x < VGA_WIDTH; x++) {
const size_t index = (VGA_HEIGHT - 1) * VGA_WIDTH + x;
state->term_buf[index] = ' ';
}
}
// Set VGA term color
void term_setColor(struct vgastate *state, uint8_t color)
{
state->term_color = color;
}
// Test various VGA functionality
void term_test(struct vgastate *term)
{
// Test line wrapping
term_writeStr(term, "Welcome to the desert of the real. I thought what I'd do was I'd pretend I was one of those deaf mutes.\n\n");
// Test colors
term_setColor(term, make_color(VGA_COLOR_BLACK, VGA_COLOR_WHITE));
term_writeStr(term, "This text should be inverse.\n");
term_setColor(term, make_color(VGA_COLOR_LIGHT_BLUE, VGA_COLOR_GREEN));
term_writeStr(term, "This text should be colorful.\n\n");
// Test scrolling
term_setColor(term, make_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK));
for (size_t i = 0; i < 20; i++) {
term_writeStr(term, "Printing some lines.\n");
for (volatile size_t j = 0; j < 100000000; j++);
}
}
// Write a string to a VGA term
void term_writeStr(struct vgastate *state, const char *data)
{
size_t dataLen = strlen(data);
for (size_t i = 0; i < dataLen; i++)
term_putChar(state, data[i]);
}

8
include/brados/printk.h
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#ifndef __brados_printk_h__
#define __brados_printk_h__
#include <video/vga.h>
int printk(struct vgastate *term, const char *fmt, ...);
#endif

8
include/brados/string.h
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@ -1,8 +0,0 @@
#ifndef __brados_string_h__
#define __brados_string_h__
#include <stddef.h>
size_t strlen(const char *str);
#endif

79
include/multiboot.h
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#ifndef __brados_multiboot_h__
#define __brados_multiboot_h__
#include <stdint.h>
// For more information on this structure, see:
// http://www.gnu.org/software/grub/manual/multiboot/multiboot.html
struct multiboot_header {
// Indicates the presence and validity of other fields
uint32_t flags;
// Present if bit 0 in 'flags' is set
uint32_t mem_lower;
uint32_t mem_upper;
// Present if bit 1 in 'flags' is set
uint32_t boot_device;
// Present if bit 2 in 'flags' is set
uint32_t cmdline;
// Present if bit 3 in 'flags' is set
uint32_t mods_count;
uint32_t mods_addr;
// Present if bits 4 or 5 are present in 'flags'
// NOTE: Bits 4 and 5 are mutually exclusive. Bit 4 indicates fields
// related to a.out kernel images, while bit 5 indicated fields related
// to ELF kernel images. Since BRaDOS is an ELF kernel, the bit 5 field
// names will be used.
uint32_t shdr_num; // "tabsize" for an a.out kernel
uint32_t shdr_size; // "strsize" for an a.out kernel
uint32_t shdr_addr; // "addr" for an a.out kernel
uint32_t shdr_shndx; // "reserved" for an a.out kernel
// Present if bit 6 in 'flags' is set
uint32_t mmap_length;
uint32_t mmap_addr;
// Present if bit 7 in 'flags' is set
uint32_t drives_length;
uint32_t drives_addr;
// Present if bit 8 in 'flags' is set
uint32_t config_table;
// Present if bit 9 in 'flags' is set
uint32_t boot_loader_name;
// Present if bit 10 in 'flags' is set
uint32_t apm_table;
// Present if bit 11 in 'flags' is set
uint32_t vbe_control_info;
uint32_t vbe_mode_info;
uint16_t vbe_mode;
uint16_t vbe_interface_seg;
uint16_t vbe_interface_off;
uint16_t vbe_interface_len;
};
struct multiboot_mmap {
uint32_t size;
uint64_t base_addr;
uint64_t length;
uint32_t type;
};
struct multiboot_mod {
uint32_t mod_start;
uint32_t mod_end;
uint32_t string;
uint32_t reserved;
};
uint32_t multiboot_getAddress();
uint32_t multiboot_getMagic();
#endif

50
include/video/vga.h
View File

@ -1,50 +0,0 @@
#ifndef __brados_video_vga_h__
#define __brados_video_vga_h__
#include <stddef.h>
#include <stdint.h>
#define VGA_BUF 0xB8000
#define VGA_WIDTH 80
#define VGA_HEIGHT 24
// VGA State
struct vgastate {
size_t term_row, term_col;
uint8_t term_color;
uint16_t *term_buf;
};
// 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
};
uint8_t make_color(enum vga_color fg, enum vga_color bg);
uint16_t make_vgaEntry(char c, uint8_t color);
void term_init(struct vgastate *state);
void term_putChar(struct vgastate *state, char c);
void term_putEntryAt(struct vgastate *state, char c, uint8_t color, size_t x, size_t y);
void term_scroll(struct vgastate *state);
void term_setColor(struct vgastate *state, uint8_t color);
void term_test(struct vgastate *term);
void term_writeStr(struct vgastate *state, const char *data);
#endif

215
kernel/brados.c
View File

@ -1,59 +1,156 @@
#include <stddef.h> #include <stddef.h>
#include <stdint.h> #include <stdint.h>
#include <brados/printk.h> // Make sure we are using the right compiler
#include <brados/string.h> #if defined(__linux__)
#include <video/vga.h> #error "You are using the wrong compiler."
#include <multiboot.h> #endif
// Make sure we are using the right compiler // Color constants
#if defined(__linux__) enum vga_color
#error "You are using the wrong compiler." {
#endif COLOR_BLACK = 0,
COLOR_BLUE = 1,
// Main kernel function COLOR_GREEN = 2,
void brados_main(uint32_t multiMagic, uint32_t multiAddr) COLOR_CYAN = 3,
{ COLOR_RED = 4,
// Initialize VGA terminal COLOR_MAGENTA = 5,
struct vgastate term; COLOR_BROWN = 6,
term_init(&term); COLOR_LIGHT_GREY = 7,
COLOR_DARK_GREY = 8,
// Welcome message COLOR_LIGHT_BLUE = 9,
printk(&term, "Welcome to BRaDOS!\n"); COLOR_LIGHT_GREEN = 10,
printk(&term, "written by L. Bradley LaBoon\n\n"); COLOR_LIGHT_CYAN = 11,
COLOR_LIGHT_RED = 12,
// Get multiboot info COLOR_LIGHT_MAGENTA = 13,
if (multiMagic != 0x2BADB002) { COLOR_LIGHT_BROWN = 14,
printk(&term, "Error! Multiboot header not present. Quitting.\n"); COLOR_WHITE = 15
return; };
}
struct multiboot_header *multiHead = (struct multiboot_header *) multiAddr; // Create a VGA color
if ((multiHead->flags >> 6) % 2 != 1) { uint8_t make_color(enum vga_color fg, enum vga_color bg)
printk(&term, "Error! Memory map not available from bootloader. Quitting.\n"); {
return; return fg | bg << 4;
} }
struct multiboot_mmap *memmap = (struct multiboot_mmap *) multiHead->mmap_addr;
// Create a VGA character
// Print memory map uint16_t make_vgaEntry(char c, uint8_t color)
printk(&term, "Memory map:\n"); {
int numEntries = multiHead->mmap_length / sizeof(struct multiboot_mmap); uint16_t c16 = c;
uint64_t lastAddr = 0; uint16_t color16 = color;
for (int i = 0; i < numEntries; i++) { return c16 | color16 << 8;
if (memmap[i].base_addr != lastAddr) { }
printk(&term, "%#llx - %#llx: Unknown\n", lastAddr, memmap[i].base_addr - 1);
lastAddr = memmap[i].base_addr; // Calculate the length of a string
} size_t strlen(const char *str)
{
printk(&term, "%#llx - %#llx: ", memmap[i].base_addr, memmap[i].base_addr + memmap[i].length - 1); size_t len = 0;
if (memmap[i].type == 1) while (str[len] != 0)
printk(&term, "Available\n"); len++;
else return len;
printk(&term, "Reserved\n"); }
lastAddr = memmap[i].base_addr + memmap[i].length; static const size_t VGA_WIDTH = 80;
} static const size_t VGA_HEIGHT = 24;
size_t term_row, term_col;
// Done uint8_t term_color;
printk(&term, "\nDone."); uint16_t *term_buf;
}
// Initialize the terminal
void term_init()
{
term_row = term_col = 0;
term_color = make_color(COLOR_LIGHT_GREY, COLOR_BLACK);
term_buf = (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;
term_buf[index] = make_vgaEntry(' ', term_color);
}
}
}
// Set the terminal color
void term_setColor(uint8_t color)
{
term_color = color;
}
// Place a character in the buffer
void term_putEntryAt(char c, uint8_t color, size_t x, size_t y)
{
const size_t index = y * VGA_WIDTH + x;
term_buf[index] = make_vgaEntry(c, color);
}
// Scroll down 1 line
void term_scroll()
{
for (size_t y = 1; y < VGA_HEIGHT; y++) {
for (size_t x = 0; x < VGA_WIDTH; x++) {
const size_t index = y * VGA_WIDTH + x;
const size_t indexBelow = (y - 1) * VGA_WIDTH + x;
term_buf[indexBelow] = term_buf[index];
}
}
for (size_t x = 0; x < VGA_WIDTH; x++) {
const size_t index = (VGA_HEIGHT - 1) * VGA_WIDTH + x;
term_buf[index] = ' ';
}
}
// Write a character to the terminal
void term_putChar(char c)
{
if (c == '\n')
term_col = VGA_WIDTH - 1;
else
term_putEntryAt(c, term_color, term_col, term_row);
if (++term_col == VGA_WIDTH) {
term_col = 0;
if (++term_row == VGA_HEIGHT) {
term_row--;
term_scroll();
}
}
}
// Write a string to the terminal
void term_writeStr(const char *data)
{
size_t dataLen = strlen(data);
for (size_t i = 0; i < dataLen; i++)
term_putChar(data[i]);
}
// Main kernel function
void brados_main()
{
term_init();
// Test printing and newlines
term_writeStr("Welcome to BRaDOS!\n");
term_writeStr("written by L. Bradley LaBoon\n\n");
// Test line wrapping
term_writeStr("The Laughing Man always says: 'I thought what I'd do was I'd pretend I was one of those deaf mutes.'\n\n");
// Test colors
term_setColor(make_color(COLOR_BLACK, COLOR_WHITE));
term_writeStr("This text should be inverse.\n");
term_setColor(make_color(COLOR_LIGHT_BLUE, COLOR_GREEN));
term_writeStr("This text should be colorful.\n\n");
// Test scrolling
term_setColor(make_color(COLOR_LIGHT_GREY, COLOR_BLACK));
for (size_t i = 0; i < 20; i++) {
term_writeStr("Printing some lines.\n");
for (size_t j = 0; j < 100000000; j++);
}
term_writeStr("Done.");
}

596
kernel/printk.c
View File

@ -1,596 +0,0 @@
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <brados/printk.h>
#include <brados/string.h>
#include <video/vga.h>
const char *BASE16 = "0123456789ABCDEF";
const char *BASE16L = "0123456789abcdef";
// Print an unsigned number as a string; return the number of characters printed
static int printNum(struct vgastate *term, uintmax_t num, unsigned int base, const char *digits)
{
if (base > strlen(digits))
return 0;
int numPrinted = 0;
int digit = num % base;
if (num >= base)
numPrinted += printNum(term, num / base, base, digits);
term_putChar(term, digits[digit]);
numPrinted++;
return numPrinted;
}
// Determines the printed length of a number
static unsigned int numLen(uintmax_t num, unsigned int base)
{
unsigned int len = 1;
while (num >= base) {
len++;
num /= base;
}
return len;
}
// Print a formatted string to the given terminal
int printk(struct vgastate *term, const char *fmt, ...)
{
int numPrinted = 0;
va_list args;
va_start(args, fmt);
// The bits of 'mode' explained:
// 0: Whether we are printing characters normally or parsing the format
// 1: Whether we are still parsing flags
// 2: Whether we are looking at width or precision (have we seen a .)
// 3: + flag
// 4: space flag
// 5: - flag
// 6: # flag
// 7: 0 flag
uint8_t mode = 0;
int length = 0;
unsigned int width = 0, precision = 0;
for (size_t i = 0; i < strlen(fmt); i++) {
if (mode % 2 == 0) {
// Begin parsing format if we reach a '%'
if (fmt[i] == '%') {
mode |= 0x01;
// Or just print the character if we're not parsing
} else {
term_putChar(term, fmt[i]);
numPrinted++;
}
continue;
}
switch (fmt[i]) {
case '%':
// Print a percent sign
term_putChar(term, '%');
numPrinted++;
mode = 0;
break;
case '+':
// Set the plus flag
if ((mode >> 1) % 2 == 0)
mode |= 0x08;
break;
case ' ':
// Set the space flag
if ((mode >> 1) % 2 == 0)
mode |= 0x10;
break;
case '-':
// Set the left-align flag
if ((mode >> 1) % 2 == 0)
mode |= 0x20;
break;
case '#':
// Set the alternate flag
if ((mode >> 1) % 2 == 0)
mode |= 0x40;
break;
case '0':
// Set the zero-pad flag
if ((mode >> 1) % 2 == 0)
mode |= 0x80;
// Next digit in width specifier
else if ((mode >> 2) % 2 == 0)
width *= 10;
// Next digit in precision specifier
else
precision *= 10;
break;
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
// Next digit in width specifier
if ((mode >> 2) % 2 == 0) {
mode |= 0x02;
width *= 10;
width += (fmt[i] - 48); // 0 = ascii 48
// Next digit in precision specifier
} else {
precision *= 10;
precision += (fmt[i] - 48);
}
break;
case '.':
// Delimit width and precision
if ((mode >> 2) % 2 == 0)
mode |= 0x06;
break;
case 'h':
// Denotes a short or char argument
mode |= 0x06;
length--;
break;
case 'l':
// Denotes a long or long long argument
mode |= 0x06;
length++;
break;
case 'z':
// Denotes a size_t argument
mode |= 0x06;
length = 3;
break;
case 'j':
// Denotes a intmax_t argument
mode |= 0x06;
length = 4;
break;
case 't':
// Denotes a ptrdiff_t argument
mode |= 0x06;
length = 5;
break;
// Print a signed integer
case 'd':
case 'i': {
intmax_t num;
uintmax_t unum;
// Pull the argument from the list
switch (length) {
case 1:
num = va_arg(args, long);
break;
case 2:
num = va_arg(args, long long);
break;
case 3:
num = va_arg(args, size_t);
break;
case 4:
num = va_arg(args, intmax_t);
break;
case 5:
num = va_arg(args, ptrdiff_t);
break;
default:
num = va_arg(args, int);
break;
}
// Get unsigned version
if (num < 0)
unum = num * -1;
else
unum = num;
// Get the length of the printed number
unsigned int len = numLen(unum, 10);
// Get the length of the printed number with formatting
unsigned int flen = len;
if (precision > len)
flen += (precision - len);
if (num < 0)
flen++;
if (num >= 0 && (mode >> 3) + (mode >> 4) > 0)
flen++;
// If specified, print preceding space padding
if ((mode >> 5) % 2 == 0) {
if (precision > 0 || (mode >> 7) % 2 == 0) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
}
// If specified print the sign
if (num < 0) {
term_putChar(term, '-');
numPrinted++;
} else if ((mode >> 3) % 2 == 1) {
term_putChar(term, '+');
numPrinted++;
} else if ((mode >> 4) % 2 == 1) {
term_putChar(term, ' ');
numPrinted++;
}
// If specified, print the precision 0s
if (precision > 0) {
for (int j = precision - len; j > 0; j--) {
term_putChar(term, '0');
numPrinted++;
}
} else if ((mode >> 7) % 2 == 1) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, '0');
numPrinted++;
}
}
// Print the number
numPrinted += printNum(term, unum, 10, BASE16);
// If specified, print succeeding spaces
if ((mode >> 5) % 2 == 1) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
mode = 0;
break;
// Print an unsigned integer
} case 'u': {
uintmax_t num;
// Pull the argument from the list
switch (length) {
case 1:
num = va_arg(args, unsigned long);
break;
case 2:
num = va_arg(args, unsigned long long);
break;
case 3:
num = va_arg(args, size_t);
break;
case 4:
num = va_arg(args, intmax_t);
break;
case 5:
num = va_arg(args, ptrdiff_t);
break;
default:
num = va_arg(args, unsigned int);
break;
}
// Get the length of the printed number
unsigned int len = numLen(num, 10);
// Get the length of the printed number with formatting
unsigned int flen = len;
if (precision > len)
flen += (precision - len);
if ((mode >> 3) % 2 == 1 || (mode >> 4) % 2 == 1)
flen++;
// If specified, print preceding space padding
if ((mode >> 5) % 2 == 0) {
if (precision > 0 || (mode >> 7) % 2 == 0) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
}
// If specified print the sign
if ((mode >> 3) % 2 == 1) {
term_putChar(term, '+');
numPrinted++;
} else if ((mode >> 4) % 2 == 1) {
term_putChar(term, ' ');
numPrinted++;
}
// If specified, print the precision 0s
if (precision > 0) {
for (int j = precision - len; j > 0; j--) {
term_putChar(term, '0');
numPrinted++;
}
} else if ((mode >> 7) % 2 == 1) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, '0');
numPrinted++;
}
}
// Print the number
numPrinted += printNum(term, num, 10, BASE16);
// If specified, print succeeding spaces
if ((mode >> 5) % 2 == 1) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
mode = 0;
break;
// Print an unsigned integer in hexadecimal
} case 'x':
case 'X': {
uintmax_t num;
// Pull the argument from the list
switch (length) {
case 1:
num = va_arg(args, unsigned long);
break;
case 2:
num = va_arg(args, unsigned long long);
break;
case 3:
num = va_arg(args, size_t);
break;
case 4:
num = va_arg(args, intmax_t);
break;
case 5:
num = va_arg(args, ptrdiff_t);
break;
default:
num = va_arg(args, unsigned int);
break;
}
// Get the length of the printed number
unsigned int len = numLen(num, 16);
// Get the length of the printed number with formatting
unsigned int flen = len;
if (precision > len)
flen += (precision - len);
if ((mode >> 3) % 2 == 1 || (mode >> 4) % 2 == 1)
flen++;
if ((mode >> 6) % 2 == 1)
flen += 2;
// If specified, print preceding space padding
if ((mode >> 5) % 2 == 0) {
if (precision > 0 || (mode >> 7) % 2 == 0) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
}
// If specified print the sign
if ((mode >> 3) % 2 == 1) {
term_putChar(term, '+');
numPrinted++;
} else if ((mode >> 4) % 2 == 1) {
term_putChar(term, ' ');
numPrinted++;
}
// If specified, print the 0x
if ((mode >> 6) % 2 == 1) {
term_putChar(term, '0');
if (fmt[i] == 'x')
term_putChar(term, 'x');
else
term_putChar(term, 'X');
numPrinted += 2;
}
// If specified, print the precision 0s
if (precision > 0) {
for (int j = precision - len; j > 0; j--) {
term_putChar(term, '0');
numPrinted++;
}
} else if ((mode >> 7) % 2 == 1) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, '0');
numPrinted++;
}
}
// Print the number
if (fmt[i] == 'x')
numPrinted += printNum(term, num, 16, BASE16L);
else
numPrinted += printNum(term, num, 16, BASE16);
// If specified, print succeeding spaces
if ((mode >> 5) % 2 == 1) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
mode = 0;
break;
// Print an unsigned integer in octal
} case 'o': {
uintmax_t num;
// Pull the argument from the list
switch (length) {
case 1:
num = va_arg(args, unsigned long);
break;
case 2:
num = va_arg(args, unsigned long long);
break;
case 3:
num = va_arg(args, size_t);
break;
case 4:
num = va_arg(args, intmax_t);
break;
case 5:
num = va_arg(args, ptrdiff_t);
break;
default:
num = va_arg(args, unsigned int);
break;
}
// Get the length of the printed number
unsigned int len = numLen(num, 8);
// Get the length of the printed number with formatting
unsigned int flen = len;
if (precision > len)
flen += (precision - len);
if ((mode >> 3) % 2 == 1 || (mode >> 4) % 2 == 1)
flen++;
if ((mode >> 6) % 2 == 1)
flen++;
// If specified, print preceding space padding
if ((mode >> 5) % 2 == 0) {
if (precision > 0 || (mode >> 7) % 2 == 0) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
}
// If specified print the sign
if ((mode >> 3) % 2 == 1) {
term_putChar(term, '+');
numPrinted++;
} else if ((mode >> 4) % 2 == 1) {
term_putChar(term, ' ');
numPrinted++;
}
// If specified, print the 0x
if ((mode >> 6) % 2 == 1) {
term_putChar(term, '0');
numPrinted++;
}
// If specified, print the precision 0s
if (precision > 0) {
for (int j = precision - len; j > 0; j--) {
term_putChar(term, '0');
numPrinted++;
}
} else if ((mode >> 7) % 2 == 1) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, '0');
numPrinted++;
}
}
// Print the number
numPrinted += printNum(term, num, 8, BASE16);
// If specified, print succeeding spaces
if ((mode >> 5) % 2 == 1) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
mode = 0;
break;
// Print a string
} case 's': {
char *s = va_arg(args, char *);
term_writeStr(term, s);
numPrinted += strlen(s);
mode = 0;
break;
// Print a character
} case 'c':
if (mode % 2 == 0)
term_putChar(term, 'c');
else
term_putChar(term, (char) va_arg(args, int));
numPrinted++;
mode = 0;
break;
// Print a pointer
case 'p': {
uintmax_t num = va_arg(args, void *);
// Get the length of the printed number
unsigned int len = numLen(num, 16);
unsigned int flen = len + 2;
precision = sizeof(void *) * 2; // A byte is 2 hex chars
// If specified, print preceding space padding
if ((mode >> 5) % 2 == 0) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
term_putChar(term, '0');
term_putChar(term, 'x');
numPrinted += 2;
// If specified, print the precision 0s
for (int j = precision - len; j > 0; j--) {
term_putChar(term, '0');
numPrinted++;
}
// Print the number
numPrinted += printNum(term, num, 16, BASE16);
// If specified, print succeeding spaces
if ((mode >> 5) % 2 == 1) {
for (int j = width - flen; j > 0; j--) {
term_putChar(term, ' ');
numPrinted++;
}
}
mode = 0;
break;
} default:
term_putChar(term, fmt[i]);
numPrinted++;
mode = 0;
break;
}
}
va_end(args);
return numPrinted;
}

12
lib/string.c
View File

@ -1,12 +0,0 @@
#include <stddef.h>
#include <brados/string.h>
// Find the length of a string
size_t strlen(const char *str)
{
size_t len = 0;
while (str[len] != 0)
len++;
return len;
}

76
arch/i586-elf/linker.ld → linker.ld
View File

@ -1,38 +1,38 @@
/* Kernel entry point */ /* Kernel entry point */
ENTRY(_start) ENTRY(_start)
/* Define the locations of the object file sections */ /* Define the locations of the object file sections */
SECTIONS SECTIONS
{ {
/* Sections begin at 1 MiB */ /* Sections begin at 1 MiB */
. = 1M; . = 1M;
/* The multiboot header needs to come first, followed by program code */ /* The multiboot header needs to come first, followed by program code */
.text BLOCK(4K) : ALIGN(4K) .text BLOCK(4K) : ALIGN(4K)
{ {
*(.multiboot) *(.multiboot)
*(.text) *(.text)
} }
/* Read-only data */ /* Read-only data */
.rodata BLOCK(4K) : ALIGN(4K) .rodata BLOCK(4K) : ALIGN(4K)
{ {
*(.rodata) *(.rodata)
} }
/* Initialized read-write data */ /* Initialized read-write data */
.data BLOCK(4K) : ALIGN(4K) .data BLOCK(4K) : ALIGN(4K)
{ {
*(.data) *(.data)
} }
/* Uninitialized read-write data and stack */ /* Uninitialized read-write data and stack */
.bss BLOCK(4K) : ALIGN(4K) .bss BLOCK(4K) : ALIGN(4K)
{ {
*(COMMON) *(COMMON)
*(.bss) *(.bss)
*(.bootstrap_stack) *(.bootstrap_stack)
} }
/* Add other sections here */ /* Add other sections here */
} }