Trying FASM instead of TCC hybrid proved to be a good choise. Binary is layed out flat and sections are not rearranged so no need to worry about Multiboot structures moving around.

Also managed to get paging (first 4M is identity mapped, but hey it's a start).
This commit is contained in:
Jarkko Toivanen 2023-08-01 05:02:17 +03:00
commit cbaa9e00f9
Signed by: jt
GPG Key ID: 9151B109B73ECAD5
17 changed files with 460 additions and 715 deletions

1
.gitignore vendored
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@ -1,5 +1,6 @@
*.elf
*.o
*.img
*.bin
mnt/
build/

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@ -1,17 +1,15 @@
all: build/kernel-i386.elf
clean:
-@rm build/*.o build/*.elf 2> /dev/null || true
-@rm *.bin 2> /dev/null || true
build/start32.o: build/ src/start32.asm
nasm -felf32 src/start32.asm -o build/start32.o
build/kernel-i386.elf: build/start32.o
tcc -m32 -nostdlib -Wl,-Ttext,0x100000 -o build/kernel-i386.elf src/*.c build/start32.o
image: build/kernel-i386.elf mount
cp build/kernel-i386.elf mnt/
start32.bin: src/*
fasm src/start32.asm start32.bin
image: start32.bin mount
cp start32.bin mnt/koalemos/
sync
qemu-multiboot: build/kernel-i386.elf
qemu-system-i386 -kernel build/kernel-i386.elf -serial stdio
qemu-multiboot: start32.bin
qemu-system-i386 -kernel start32.bin -serial stdio
qemu-image: image
qemu-system-i386 koalemos.img -serial stdio

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@ -3,7 +3,4 @@ Multiboot compatible stupid useless OS-like project.
## Compatibility
32bit x86 legacy BIOS system
## Building
NASM and TinyCCompiler are used.
TCC might need manual compilation for 32bit crosscompilation
on 64bit systems.
Just download the source and `make cross` or something.
FASM is used as the assembler.

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@ -1,24 +0,0 @@
#include "framebuffer.h"
static unsigned long fb_address;
static unsigned long fb_pitch;
static unsigned short fb_width, fb_height;
static unsigned char fb_bpp, fb_bytespp;
static unsigned char fb_rpos, fb_bpos, fb_gpos;
void initfb(unsigned long addr, unsigned short w, unsigned short h, unsigned char bpp, unsigned long pitch, unsigned char rpos, unsigned char gpos, unsigned char bpos) {
fb_address = addr;
fb_pitch = pitch;
fb_width = w;
fb_height = h;
fb_bpp = bpp;
fb_bytespp = bpp/8;
fb_rpos = rpos;
fb_gpos = gpos;
fb_bpos = bpos;
}
void putpixel(unsigned short x, unsigned short y, unsigned char r, unsigned char g, unsigned char b, unsigned char a) {
if (x>fb_width || y> fb_height) return;
*((unsigned long *)(fb_address + y*fb_pitch + x*fb_bytespp)) = r<<fb_rpos | g<<fb_gpos | b<<fb_bpos;
}

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@ -1,7 +0,0 @@
#ifndef _FRAMEBUFFER_H
#define _FRAMEBUFFER_H 1
void initfb(unsigned long addr, unsigned short w, unsigned short h, unsigned char bpp, unsigned long pitch, unsigned char rpos, unsigned char gpos, unsigned char bpos);
void putpixel(unsigned short x, unsigned short y, unsigned char r, unsigned char g, unsigned char b, unsigned char a);
#endif

98
src/itoa.asm Normal file
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;; Modified from: https://gist.github.com/SplittyDev/8e728627012e57ac0deac196660014fb
;
; Routine to convert a 32-bit integer to a string.
; Registers are preserved.
;
; EAX: Source integer
; EBX: Target address
; ECX: Base
;
; Internal register layout:
; start:
; EAX: Source integer
; ECX: Target address
; EDX: Base
; checknegative:
; EAX: Source integer
; EBX: Target address (original)
; ECX: Target address (active)
; divrem:
; EAX: Source integer
; ECX: Target address (active)
; EDX: Base / Result
; reverse:
; EBX: Target address (original)
; ECX: Target address (active)
; EDX: Target address (temporary)
;
__uitoa:
.start:
push ebp
mov ebp, esp
push eax
push ebx
push ecx
push edx
mov eax, [ebp+8]
mov ecx, [ebp+12]
mov ebx, [ebp+16]
mov edx, ecx
mov ecx, ebx
;.checknegative:
; test eax, eax
; jns .divrem
; mov byte [ecx], 0x2D
; inc ecx
; mov ebx, ecx
; neg eax
.divrem:
push edx
push ecx
mov ecx, edx
xor edx, edx
div ecx
mov byte dl, [__itoacvt + edx]
pop ecx
mov byte [ecx], dl
pop edx
inc ecx
cmp eax, 0x00
jne .divrem
mov byte [ecx], 0x00
dec ecx
.reverse:
cmp ebx, ecx
jge .end
mov byte dl, [ebx]
mov byte al, [ecx]
mov byte [ebx], al
mov byte [ecx], dl
inc ebx
dec ecx
jmp .reverse
.end:
pop edx
pop ecx
pop ebx
pop eax
pop ebp
ret
;
; Conversion table for __itoa.
; Works for bases [2 ... 36].
;
__itoacvt:
db '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
;
; Buffer to store the result of __itoa in.
;
align 64
__itoabuf32:
rb 36

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@ -1,83 +0,0 @@
#include "multiboot.h"
#include "framebuffer.h"
#include "serial.h"
#include "xtoa.h"
static inline void outb(unsigned short port, unsigned char val) {
asm volatile ("outb %0, %1" : : "a"(val), "Nd"(port) : "memory");
}
static inline unsigned char inb(unsigned short port) {
unsigned char ret;
asm volatile("inb %1, %0" : "=a"(ret) : "Nd"(port) : "memory");
return ret;
}
void kmain (unsigned int mbootmagick, multiboot_info_t* mbootinfo) {
// Cursor disabling
outb(0x3D4, 0x0A);
outb(0x3D5, 0x20);
int serial_initialized = serial_init();
serial_write_string("\n=== KoalemOS ===\n");
// Check multiboot header
if (mbootmagick != MULTIBOOT_BOOTLOADER_MAGIC) {
return;
}
serial_write_string("\nMultiboot flags: ");
serial_write_string(itoa(mbootinfo->flags, 2));
// Check videomode
if (mbootinfo->flags & MULTIBOOT_INFO_VBE_INFO) {
serial_write_string("\nVBE Mode: 0x");
serial_write_string(itoa(mbootinfo->vbe_mode, 16));
}
if (!(mbootinfo->flags & MULTIBOOT_INFO_FRAMEBUFFER_INFO)) {
serial_write_string("\nVideo info not available");
return;
}
serial_write_string("\nFramebuffer: ");
serial_write_string("\n Address: 0x");
serial_write_string(ultoa(mbootinfo->framebuffer_addr, 16));
serial_write_string("\n Dimensions: ");
serial_write_string(itoa(mbootinfo->framebuffer_width, 10));
serial_write_string("X");
serial_write_string(itoa(mbootinfo->framebuffer_height, 10));
serial_write_string("x");
serial_write_string(itoa(mbootinfo->framebuffer_bpp, 10));
serial_write_string("\n Pitch: ");
serial_write_string(itoa(mbootinfo->framebuffer_pitch, 10));
serial_write_string("\n RPos:");
serial_write_string(itoa(mbootinfo->framebuffer_red_field_position, 10));
serial_write_string("\n GPos:");
serial_write_string(itoa(mbootinfo->framebuffer_green_field_position, 10));
serial_write_string("\n BPos:");
serial_write_string(itoa(mbootinfo->framebuffer_blue_field_position, 10));
serial_write_string("\nMemory: ");
serial_write_string("\n lower: ");
serial_write_string(uitoa(mbootinfo->mem_lower, 10));
serial_write_string(" k");
serial_write_string("\n upper: ");
serial_write_string(uitoa(mbootinfo->mem_upper/1024, 10));
serial_write_string(" M");
initfb(mbootinfo->framebuffer_addr, mbootinfo->framebuffer_width, mbootinfo->framebuffer_height, mbootinfo->framebuffer_bpp, mbootinfo->framebuffer_pitch, mbootinfo->framebuffer_red_field_position, mbootinfo->framebuffer_green_field_position, mbootinfo->framebuffer_blue_field_position);
int x, y, i;
unsigned char c = 0;
for(;;) {
for(y=0; y < mbootinfo->framebuffer_height; y++) {
for(x=0; x < mbootinfo->framebuffer_width; x++) {
putpixel(x, y, c, c, c, 0xff);
}
}
c+=4;
}
serial_write_string("\nExecution finished, halting...");
}

118
src/mbootinfo.asm Normal file
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mbootgetinfo:
push ebp
mov ebp, esp
push ebx
push esi
push edi
cld
mov eax, [ebp+8]
cmp eax, 0x2badb002
jne mbootnomagic
mov ebx, [ebp+12]
mov eax, [ebx]
mov [mbootinfo.flags], eax
;; Get memoryinformation
test eax, 1b
jz mbootnomeminfo
mov eax, [ebx+4]
mov [mbootinfo.mem_lower], eax
mov eax, [ebx+8]
mov [mbootinfo.mem_upper], eax
;; Get videoinformation
test [mbootinfo.flags], (1 shl 02)
jz mbootnovideoinfo
mov esi, ebx
add esi, 88
mov eax, [esi]
mov [mbootinfo.fb_addr], eax
add esi, 8
mov eax, [esi]
mov [mbootinfo.fb_pitch], eax
add esi, 4
mov eax, [esi]
mov [mbootinfo.fb_width], eax
add esi, 4
mov eax, [esi]
mov [mbootinfo.fb_height], eax
add esi, 4
mov al, [esi]
cmp al, 32
je .bppokay
cmp al, 24
je .bppokay
jmp mbootunsupportedfbbpp
.bppokay:
mov [mbootinfo.fb_bpp], al
inc esi
mov al, [esi]
cmp al, 1
jne mbootunsupportedfbtype
mov [mbootinfo.fb_type], al
inc esi
;; r/g/b positions and masks
mov ecx, 6
mov edi, mbootinfo.fb_rpos
rep movsb
.done:
pop edi
pop esi
pop ebx
pop ebp
ret
mbootnomagic:
push .msg
call serialwrite
jmp hang
.msg db "No multiboot magic!", 10, 0
mbootnomeminfo:
push .msg
call serialwrite
jmp hang
.msg db "No memoryinfo!", 10, 0
mbootnovideoinfo:
push .msg
call serialwrite
jmp hang
.msg db "No videoryinfo!", 10, 0
mbootunsupportedfbtype:
push .msg
call serialwrite
jmp hang
.msg db "Unsupported framebuffer type: only direct RGB is supported!", 10, 0
mbootunsupportedfbbpp:
push .msg
call serialwrite
jmp hang
.msg db "Unsupported bitdepth: only 24 and 32 bpp supported!", 10, 0
mbootinfo:
.flags dd 0
.mem_lower dd 0
.mem_upper dd 0
.fb_addr dd 0
.fb_pitch dd 0
.fb_width dd 0
.fb_height dd 0
.fb_bpp db 0
.fb_type db 0
.fb_rpos db 0
.fb_rmasksize db 0
.fb_gpos db 0
.fb_gmasksize db 0
.fb_bpos db 0
.fb_bmasksize db 0

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@ -1,274 +0,0 @@
/* 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 */

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src/serial.asm Normal file
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SERIAL_PORT equ 0x3f8
serialinitialized db 0
serialinit:
push ax
;Disable ints
mov dx, SERIAL_PORT+1
mov al, 0x00
out dx, al
;Enable DLAB baud divisor and set 3 (38400 baud)
mov al, 0x80
mov dx, SERIAL_PORT+3
out dx, al
;Baud divisor lo byte
mov al, 0x03
mov dx, SERIAL_PORT
out dx, al
;Baud divisor hi byte
mov al, 0x00
mov dx, SERIAL_PORT+1
out dx, al
;8bits, no parity, one stop bit
mov al, 0x03
mov dx, SERIAL_PORT+3
out dx, al
;Enable+clear FIFO, 14-byte threshold
mov al, 0xc7
mov dx, SERIAL_PORT+2
out dx, al
;IRQs enabled, RTS/DSR set
mov al, 0x0b
mov dx, SERIAL_PORT+4
out dx, al
;Set loopback for test purposes
mov al, 0x1e
out dx, al
;; Check if serial is workie
mov al, 0xae
mov dx, SERIAL_PORT
out dx, al
in al, dx
cmp al, 0xae
jne .end
;; Set serial to normal operation
mov dx, SERIAL_PORT+4
mov al, 0x0f
out dx, al
mov [serialinitialized], 1
.end:
pop ax
ret
.errormsg db "Serial init failed", 0
serialwrite:
cmp [serialinitialized], 0
je .notinitialized
push ebp
mov ebp, esp
push esi
push ax
cld
mov esi, [ebp+8]
.loop:
mov dx, SERIAL_PORT+5
.wait:
in al, dx
and al, 0x20
jz .wait
lodsb
or al, al
jz .done
mov dx, SERIAL_PORT
out dx, al
jmp .loop
.done:
pop ax
pop esi
pop ebp
ret
.notinitialized:
ret

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@ -1,49 +0,0 @@
#include "serial.h"
#define PORT 0x3f8 // COM1
static inline void outb(unsigned short port, unsigned char val) {
asm volatile ("outb %0, %1" : : "a"(val), "Nd"(port) : "memory");
}
static inline unsigned char inb(unsigned short port) {
unsigned char ret;
asm volatile("inb %1, %0" : "=a"(ret) : "Nd"(port) : "memory");
return ret;
}
int serial_init() {
outb(PORT + 1, 0x00); // Disable all interrupts
outb(PORT + 3, 0x80); // Enable DLAB (set baud rate divisor)
outb(PORT + 0, 0x03); // Set divisor to 3 (lo byte) 38400 baud
outb(PORT + 1, 0x00); // (hi byte)
outb(PORT + 3, 0x03); // 8 bits, no parity, one stop bit
outb(PORT + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold
outb(PORT + 4, 0x0B); // IRQs enabled, RTS/DSR set
outb(PORT + 4, 0x1E); // Set in loopback mode, test the serial chip
outb(PORT + 0, 0xAE); // Test serial chip (send byte 0xAE and check if serial
// returns same byte)
// Check if serial is faulty (i.e: not same byte as sent)
if (inb(PORT + 0) != 0xAE) {
return 1;
}
// If serial is not faulty set it in normal operation mode
// (not-loopback with IRQs enabled and OUT#1 and OUT#2 bits enabled)
outb(PORT + 4, 0x0F);
return 0;
}
static int serial_is_transmit_empty() { return inb(PORT + 5) & 0x20; }
static void serial_write_char(char chr) {
while (serial_is_transmit_empty() == 0);
outb(PORT, chr);
}
void serial_write_string(const char* text) {
int i = 0;
while(text[i]) {
serial_write_char(text[i]);
i++;
}
}

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#ifndef HEADER_SERIAL
#define HEADER_SERIAL
int serial_init(void);
void serial_write_string(const char* text);
#endif

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@ -1,47 +1,166 @@
format binary
use32
org 0x100000
MULTIBOOT_HEADER_MAGIC equ 0x1BADB002
MULTIBOOT_PAGE_ALIGN equ 1 << 0
MULTIBOOT_MEMORY_INFO equ 1 << 1
MULTIBOOT_VIDEO_REQUEST equ 0 << 2
MULTIBOOT_AOUT_KLUDGE equ 0 << 16
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO | MULTIBOOT_VIDEO_REQUEST
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO | MULTIBOOT_VIDEO_REQUEST | MULTIBOOT_AOUT_KLUDGE
MULTIBOOT_PAGE_ALIGN equ (1 shl 0)
MULTIBOOT_MEMORY_INFO equ (1 shl 1)
MULTIBOOT_VIDEO_REQUEST equ (1 shl 2)
MULTIBOOT_AOUT_KLUDGE equ (1 shl 16)
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN or MULTIBOOT_MEMORY_INFO or MULTIBOOT_VIDEO_REQUEST
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN or MULTIBOOT_MEMORY_INFO or MULTIBOOT_VIDEO_REQUEST or MULTIBOOT_AOUT_KLUDGE
MULTIBOOT_CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
section .multiboot
align 4
multiboot:
dd MULTIBOOT_HEADER_MAGIC
dd MULTIBOOT_HEADER_FLAGS
dd MULTIBOOT_CHECKSUM
dd 0 ; header address
dd 0 ; load address
dd 0 ; load end address
dd 0 ; bss end address
dd 0 ; entry address
dd multiboot ; header address
dd 0x100000 ; load address
dd bss ; load end address
dd stack_top ; bss end address
dd start ; entry address
dd 0 ; video mode_type (0:fb, 1:txt) (set flags[2]!)
dd 1024 ; video width
dd 768 ; video height
dd 32 ; video depth
section .bss
align 16
stack_bottom:
resb 16384
stack_top:
section .text
global _start
extern kmain
_start:
start:
; Setup stack
mov ebp, stack_top
mov esp, stack_top
; Call the main kernel function.
push ebx
push eax
call kmain
.hang:
call serialinit
push stuff.bootmsg
call serialwrite
add esp, 4
call mbootgetinfo
add esp, 2*4
mov eax, [mbootinfo.fb_addr]
mov dword [eax], 0xffffffff
push stuff.fbaddrmsgpfx
call serialwrite
add esp, 4
sub esp, 36 ;Reserve stack for return
push dword esp ;Destination address
push dword 16 ;Base
push dword [mbootinfo.fb_addr] ;source
call __uitoa
add esp, 3*4
push esp
call serialwrite
add esp, 4
push stuff.fbdimensionsmsgpfx
call serialwrite
add esp, 4
push dword esp ;destination address
push dword 10 ;base
push dword [mbootinfo.fb_width]
call __uitoa
add esp, 3*4
push esp
call serialwrite
add esp, 4
push stuff.x
call serialwrite
add esp, 4
push dword esp ;destination address
push dword 10 ;base
push dword [mbootinfo.fb_height]
call __uitoa
add esp, 3*4
push esp
call serialwrite
add esp, 4
push stuff.x
call serialwrite
add esp, 4
push dword esp ;destination address
push dword 10 ;base
xor eax, eax
mov al, [mbootinfo.fb_bpp]
push dword eax
call __uitoa
add esp, 3*4
push esp
call serialwrite
add esp, 4
add esp, 36 ;Clean reserved uitoa return string from stack
;; Setup paging
;; Clear pagedir
cld
mov eax, 0x00000002 ;Supervisor only, Write enabled, Not present
mov ecx, 1024
mov edi, pagedir
rep stosd
;; Clear pagetable1
mov edi, pagetable1
mov cx, 0
.clearpt1loop:
mov eax, 0x00001000
mul ecx
or eax, 011b ;supervisor, rw, present
stosd
inc cx
cmp cx, 1024
jne .clearpt1loop
;; put table1 in dir
mov eax, pagetable1
or eax, 011b ;supervisor, rw, present
mov [pagedir], eax
;; Enable paging
mov eax, pagedir
mov cr3, eax
mov eax, cr0
or eax, 0x80000000
mov cr0, eax
jmp hang
hang:
push .msg
call serialwrite
cli
.loop:
hlt
jmp .hang
jmp .loop
.msg db 10, "Halting...", 10, 0
include "src/serial.asm"
include "src/mbootinfo.asm"
include "src/itoa.asm"
stuff:
.bootmsg db 10, "=== KoalemOS ===", 10, 0
.fbaddrmsgpfx db 10, "Framebuffer address: 0x", 0
.fbdimensionsmsgpfx db 10, "Framebuffer dimensions: ", 0
.x db "x", 0
bss:
align 4096
pagedir:
rb 4096
align 4096
pagetable1:
rb 4096
align 4096
stack_bottom:
rb 16384
stack_top:

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@ -1,97 +0,0 @@
#include "vga.h"
#define VGA_WIDTH 80
#define VGA_HEIGHT 25
#define VGA_MEM_ADDR 0xb8000
#define CURSOR_HOME (VGA_HEIGHT-1)*VGA_WIDTH
#define CURSOR_CHR 177;
unsigned int cursor_loc = CURSOR_HOME;
unsigned char fgcolor;
unsigned char bgcolor;
unsigned short blank;
static unsigned char vga_entry_color(enum vga_color fg, enum vga_color bg) {
return fg | bg << 4;
}
unsigned short vga_blank_entry() {
return vga_entry_color(fgcolor, bgcolor) << 8;
}
void draw_cursor(void) {
*((unsigned char *)VGA_MEM_ADDR + cursor_loc * 2) = CURSOR_CHR;
*((unsigned char *)VGA_MEM_ADDR+1 + cursor_loc * 2) = vga_entry_color(fgcolor, bgcolor);
}
void vga_set_color(enum vga_color fg, enum vga_color bg) {
fgcolor = fg;
bgcolor = bg;
}
void vga_init(enum vga_color fg, enum vga_color bg) {
vga_set_color(fg, bg);
blank = vga_blank_entry();
cls();
}
void cls(void) {
int i;
for (i=0; i<VGA_HEIGHT*VGA_WIDTH;i++) {
*((unsigned short *) VGA_MEM_ADDR+i) = blank;
}
}
void scroll(void) {
int y;
int x;
*((unsigned short *) VGA_MEM_ADDR+cursor_loc) = blank;
for (y=0;y<VGA_HEIGHT;y++) {
for (x = 0;x<VGA_WIDTH;x++) {
*((unsigned short *) VGA_MEM_ADDR+y*VGA_WIDTH+x) = *((unsigned short *) VGA_MEM_ADDR+(y+1)*VGA_WIDTH+x);
}
}
for (x=0;x<VGA_WIDTH;x++) {
*((unsigned short *) VGA_MEM_ADDR+CURSOR_HOME+x) = blank;
}
cursor_loc = CURSOR_HOME;
draw_cursor();
}
void putchar(unsigned char chr) {
if (chr == '\n') {
scroll();
return;
}
*((unsigned char *) VGA_MEM_ADDR+cursor_loc * 2) = chr;
*((unsigned char *) VGA_MEM_ADDR+1+cursor_loc * 2) = vga_entry_color(fgcolor, bgcolor);
cursor_loc++;
if (cursor_loc >= VGA_HEIGHT*VGA_WIDTH) {
scroll();
}
draw_cursor();
}
void vga_write(const char* text) {
int i = 0;
while(text[i]) {
putchar(text[i]);
i++;
}
}
void vga_write_color( const char* text, enum vga_color fg, enum vga_color bg) {
unsigned char prevfg = fgcolor;
unsigned char prevbg = bgcolor;
vga_set_color(fg, bg);
vga_write(text);
fgcolor = prevfg;
bgcolor = prevbg;
}
void vga_write_line(const char* text) {
if (cursor_loc != CURSOR_HOME) {
scroll();
}
vga_write(text);
scroll();
}
void vga_write_line_color(const char* text, enum vga_color fg, enum vga_color bg) {
unsigned char prevfg = fgcolor;
unsigned char prevbg = bgcolor;
vga_set_color(fg, bg);
vga_write_line(text);
fgcolor = prevfg;
bgcolor = prevbg;
}

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@ -1,24 +0,0 @@
#ifndef HEADER_VGA
#define HEADER_VGA
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_ORANGE = 6,
VGA_COLOR_GREY = 7,
VGA_COLOR_GRAY = 7,
};
void cls(void);
void vga_init(enum vga_color fg, enum vga_color bg);
void vga_write(const char* text);
void vga_write_color( const char* text, enum vga_color fg, enum vga_color bg);
void vga_write_line(const char* text);
void vga_write_line_color( const char* text, enum vga_color fg, enum vga_color bg);
#endif

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@ -1,100 +0,0 @@
#include "xtoa.h"
char* itoa(int value, int base) {
char* result;
// check that the base if valid
if (base < 2 || base > 36) { *result = '\0'; return result; }
char* ptr = result, *ptr1 = result, tmp_char;
int tmp_value;
do {
tmp_value = value;
value /= base;
*ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
} while ( value );
// Apply negative sign
if (tmp_value < 0) *ptr++ = '-';
*ptr-- = '\0';
while(ptr1 < ptr) {
tmp_char = *ptr;
*ptr--= *ptr1;
*ptr1++ = tmp_char;
}
return result;
}
char* uitoa(unsigned int value, int base) {
char* result;
// check that the base if valid
if (base < 2 || base > 36) { *result = '\0'; return result; }
char* ptr = result, *ptr1 = result, tmp_char;
int tmp_value;
do {
tmp_value = value;
value /= base;
*ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
} while ( value );
*ptr-- = '\0';
while(ptr1 < ptr) {
tmp_char = *ptr;
*ptr--= *ptr1;
*ptr1++ = tmp_char;
}
return result;
}
char* ltoa(long value, int base) {
char* result;
// check that the base if valid
if (base < 2 || base > 36) { *result = '\0'; return result; }
char* ptr = result, *ptr1 = result, tmp_char;
int tmp_value;
do {
tmp_value = value;
value /= base;
*ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
} while ( value );
// Apply negative sign
if (tmp_value < 0) *ptr++ = '-';
*ptr-- = '\0';
while(ptr1 < ptr) {
tmp_char = *ptr;
*ptr--= *ptr1;
*ptr1++ = tmp_char;
}
return result;
}
char* ultoa(unsigned long value, int base) {
char* result;
// check that the base if valid
if (base < 2 || base > 36) { *result = '\0'; return result; }
char* ptr = result, *ptr1 = result, tmp_char;
int tmp_value;
do {
tmp_value = value;
value /= base;
*ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
} while ( value );
// Apply negative sign
//if (tmp_value < 0) *ptr++ = '-';
*ptr-- = '\0';
while(ptr1 < ptr) {
tmp_char = *ptr;
*ptr--= *ptr1;
*ptr1++ = tmp_char;
}
return result;
}

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@ -1,9 +0,0 @@
#ifndef HEADER_XTOA
#define HEADER_XTOA
char* itoa(int value, int base);
char* uitoa(unsigned int value, int base);
char* ltoa(long value, int base);
char* ultoa(unsigned long value, int base);
#endif