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Split up source and added basic support for different targets.

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This commit is contained in:
Patrick
2024-01-12 17:19:27 +01:00
parent 219a48c616
commit 408e06b2e0
29 changed files with 559 additions and 36 deletions
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17
targets/_any/SConscript Normal file
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Import('env')
any_target_sources = Split('''
src/app/main.cpp
src/os/panic.cpp
src/os/tty.cpp
src/cstdlib/assert.cpp
src/cstdlib/stdio.cpp
src/cstdlib/stdlib.cpp
src/cstdlib/string.cpp
''')
env.Append(KERNEL_SOURCES = [env.File(f) for f in any_target_sources])
Return('env')

27
targets/_any/include/assert.h Normal file
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#pragma once
#if !defined(BAD_APPLE_OS_ASSERT_H_INCLUDED)
#define BAD_APPLE_OS_ASSERT_H_INCLUDED
#include "./detail/common.h"
BA_EXTERN_C_BEGIN
#if defined(NDEBUG)
#define assert(condition) ((void) 0)
#else
#define assert(condition) \
if (!(condition)) \
{ \
__ba__assert_fail(__FILE__, __LINE__, #condition); \
}
#endif
#if !defined(NDEBUG)
BA_CXX_NORETURN void __ba__assert_fail(const char* filename, int line, const char* condition) BA_CXX_NOEXCEPT;
#endif
BA_EXTERN_C_END
#endif // !defined(BAD_APPLE_OS_ASSERT_H_INCLUDED)

21
targets/_any/include/detail/common.h Normal file
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#pragma once
#if !defined(BAD_APPLE_OS_DETAIL_ATTRIBUTES_H_INCLUDED)
#define BAD_APPLE_OS_DETAIL_ATTRIBUTES_H_INCLUDED
#if defined(__cplusplus)
#define BA_CXX_NODISCARD [[nodiscard]]
#define BA_CXX_NORETURN [[noreturn]]
#define BA_CXX_NOEXCEPT noexcept
#define BA_EXTERN_C_BEGIN extern "C" {
#define BA_EXTERN_C_END }
#else
#define BA_CXX_NODISCARD
#define BA_CXX_NORETURN
#define BA_CXX_NOEXCEPT
#define BA_EXTERN_C_BEGIN
#define BA_EXTERN_C_END
#endif
#endif // !defined(BAD_APPLE_OS_DETAIL_ATTRIBUTES_H_INCLUDED)

10
targets/_any/include/os/panic.hpp Normal file
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#pragma once
#if !defined(BAD_APPLE_OS_PANIC_HPP_INCLUDED)
#define BAD_APPLE_OS_PANIC_HPP_INCLUDED
[[noreturn]] void panic(const char* message) noexcept;
[[noreturn]] void panicf(const char* format, ...) noexcept;
#endif // !defined(BAD_APPLE_OS_PANIC_HPP_INCLUDED)

46
targets/_any/include/os/tty.hpp Normal file
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#pragma once
#if !defined(OS_TTY_HPP_INCLUDED)
#define OS_TTY_HPP_INCLUDED 1
#include <stddef.h>
#include <stdint.h>
namespace tty
{
enum class VgaColor : uint8_t
{
BLACK = 0,
BLUE = 1,
GREEN = 2,
CYAN = 3,
RED = 4,
MAGENTA = 5,
BROWN = 6,
LIGHT_GREY = 7,
DARK_GREY = 8,
LIGHT_BLUE = 9,
LIGHT_GREEN = 10,
LIGHT_CYAN = 11,
LIGHT_RED = 12,
LIGHT_MAGENTA = 13,
LIGHT_BROWN = 14,
WHITE = 15
};
struct VgaDoubleColor
{
VgaColor foreground : 4 = VgaColor::LIGHT_GREY;
VgaColor background : 4 = VgaColor::BLACK;
};
void initialize();
void setColor(VgaDoubleColor color);
void putEntryAt(char chr, VgaDoubleColor color, size_t posX, size_t posY);
void putChar(char chr);
void write(const char* data, size_t size);
void write(const char* data);
} // namespace tty
#endif // OS_TTY_HPP_INCLUDED

19
targets/_any/include/stdio.h Normal file
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#pragma once
#if !defined(BAD_APPLE_OS_STDIO_H_INCLUDED)
#define BAD_APPLE_OS_STDIO_H_INCLUDED
#include <stdarg.h>
#include "./detail/common.h"
BA_EXTERN_C_BEGIN
int putchar(int chr) BA_CXX_NOEXCEPT;
int puts(const char* str) BA_CXX_NOEXCEPT;
int printf(const char* format, ...) BA_CXX_NOEXCEPT;
int vprintf(const char* format, va_list vlist) BA_CXX_NOEXCEPT;
BA_EXTERN_C_END
#endif // !defined(BAD_APPLE_OS_STDIO_H_INCLUDED)

18
targets/_any/include/stdlib.h Normal file
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#pragma once
#if !defined(BAD_APPLE_OS_STDLIB_H_INCLUDED)
#define BAD_APPLE_OS_STDLIB_H_INCLUDED
#include <stddef.h>
#include "./detail/common.h"
BA_EXTERN_C_BEGIN
BA_CXX_NORETURN void abort();
BA_CXX_NODISCARD void* malloc(size_t size) BA_CXX_NOEXCEPT;
void free(void* ptr) BA_CXX_NOEXCEPT;
BA_EXTERN_C_END
#endif // !defined(BAD_APPLE_OS_STDLIB_H_INCLUDED)

21
targets/_any/include/string.h Normal file
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#pragma once
#if !defined(BAD_APPLE_OS_STRING_H_INCLUDED)
#define BAD_APPLE_OS_STRING_H_INCLUDED
#include <stddef.h>
#include "./detail/common.h"
BA_EXTERN_C_BEGIN
BA_CXX_NODISCARD int memcmp(const void* lhs, const void* rhs, size_t count) BA_CXX_NOEXCEPT;
void memcpy(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
void memmove(void* dest, const void* src, size_t count) BA_CXX_NOEXCEPT;
void* memset(void* dest, int value, size_t count) BA_CXX_NOEXCEPT;
BA_CXX_NODISCARD size_t strlen(const char* str) BA_CXX_NOEXCEPT;
BA_EXTERN_C_END
#endif // !defined(BAD_APPLE_OS_STRING_H_INCLUDED)

4
targets/_any/src/app/main.cpp Normal file
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extern "C" void main()
{
}

20
targets/_any/src/cstdlib/assert.cpp Normal file
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#include <assert.h>
#include <cstdio>
#include <cstdlib>
extern "C"
{
#if !defined(NDEBUG)
void __ba__assert_fail(const char* filename, int line, const char* condition) noexcept
{
std::printf(R"(
Assertion failed:
File: %s
Line: %d
Condition: %s)" "\n", filename, line, condition);
std::abort();
}
#endif
} // extern "C"

208
targets/_any/src/cstdlib/stdio.cpp Normal file
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#include <stdio.h>
#include <cassert>
#include <cstring>
#include <stdarg.h>
#include "os/tty.hpp"
extern "C"
{
namespace
{
int printInt(int value)
{
if (value == 0)
{
putchar('0');
return 1;
}
if (value < 0)
{
putchar('-');
return printInt(-value) + 1;
}
char digits[10]; // 2147483647 has 10 digits
char* pos = &digits[0];
while (value > 0)
{
*pos = static_cast<char>('0' + (value % 10));
value /= 10;
++pos;
}
for (char* chr = pos - 1; chr >= digits; --chr)
{
putchar(*chr);
}
return pos - digits;
}
int printUInt(uint64_t value)
{
if (value == 0)
{
putchar('0');
return 1;
}
char digits[20]; // 18,446,744,073,709,551,615 has 20 digits
char* pos = &digits[0];
while (value > 0)
{
*pos = static_cast<char>('0' + (value % 10));
value /= 10;
++pos;
}
for (char* chr = pos - 1; chr >= digits; --chr)
{
putchar(*chr);
}
return pos - digits;
}
int printHexInt(uint64_t value)
{
if (value == 0)
{
putchar('0');
return 1;
}
char digits[16]; // FFFFFFFFFFFFFFFF has 16 digits
char* pos = &digits[0];
while (value > 0)
{
const uint64_t digit = (value % 16);
if (digit < 10)
{
*pos = static_cast<char>('0' + digit);
}
else
{
*pos = static_cast<char>('A' + digit - 10);
}
value /= 16;
++pos;
}
for (char* chr = pos - 1; chr >= digits; --chr)
{
putchar(*chr);
}
return pos - digits;
}
int printPointer(void* ptr)
{
return printHexInt(reinterpret_cast<uint64_t>(ptr));
}
int printString(const char* str)
{
const size_t len = std::strlen(str);
for (size_t idx = 0; idx < len; ++idx)
{
putchar(str[idx]);
}
return static_cast<int>(len);
}
int printByteSize(size_t bytes)
{
const char* suffixes[] = {
"B", "KiB", "MiB", "GiB", "TiB"
};
int suffixIdx = 0;
for (; suffixIdx < sizeof(suffixes) / sizeof(suffixes[0]); ++suffixIdx)
{
if (bytes < 1024) {
break;
}
bytes /= 1024;
}
return printUInt(bytes) + printString(suffixes[suffixIdx]);
}
}
int putchar(int chr) noexcept
{
tty::putChar(static_cast<char>(chr));
return 0;
}
int puts(const char* str) noexcept
{
tty::write(str);
tty::putChar('\n');
return 0;
}
int printf(const char* format, ...) noexcept
{
va_list parameters;
va_start(parameters, format);
const int result = vprintf(format, parameters);
va_end(parameters);
return result;
}
int vprintf(const char* format, va_list vlist) BA_CXX_NOEXCEPT
{
int result = 0;
const char* pos = format;
while (*pos != '\0')
{
if (*pos == '%')
{
++pos;
switch (*pos)
{
case '%':
putchar('%');
++result;
break;
case '\0':
// TODO: invalid format string, do something
assert(!"Invalid format string, ends with %.");
return -1;
case 'b':
result += printByteSize(va_arg(vlist, size_t));
break;
case 'c':
{
const char chr = static_cast<char>(va_arg(vlist, int));
putchar(chr);
++result;
break;
}
case 's':
result += printString(va_arg(vlist, const char*));
break;
case 'd':
result += printInt(va_arg(vlist, int));
break;
case 'p':
result += printPointer(va_arg(vlist, void*));
break;
case 'X':
result += printHexInt(va_arg(vlist, unsigned));
break;
default:
assert(!"Invalid format string, unknown format identifier.");
return -1;
}
} else
{
putchar(*pos);
}
++pos;
}
++result;
return result;
}
} // extern "C"

105
targets/_any/src/cstdlib/stdlib.cpp Normal file
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#include <stdlib.h>
#include <stddef.h>
#include "os/tty.hpp"
namespace
{
inline const size_t INIT_MALLOC_SPACE_ELEMENTS = 1024;
inline const size_t INIT_MALLOC_SPACE_BYTES = INIT_MALLOC_SPACE_ELEMENTS * sizeof(max_align_t);
max_align_t gInitMallocSpace[INIT_MALLOC_SPACE_ELEMENTS];
struct MallocBlock
{
size_t elements;
MallocBlock* nextBlock;
};
struct AllocInfo
{
size_t elements;
};
static_assert(sizeof(MallocBlock) <= sizeof(max_align_t));
static_assert(sizeof(AllocInfo) <= sizeof(max_align_t));
MallocBlock* gNextBlock = []()
{
MallocBlock* initialBlock = reinterpret_cast<MallocBlock*>(gInitMallocSpace);
initialBlock->elements = INIT_MALLOC_SPACE_ELEMENTS;
initialBlock->nextBlock = nullptr;
return initialBlock;
}();
}
void __ba_registerAllocatableMemory(void* memory, size_t size) noexcept
{
if (size < sizeof(max_align_t))
{
return;
}
MallocBlock* newBlock = static_cast<MallocBlock*>(memory);
newBlock->nextBlock = gNextBlock;
newBlock->elements = size / sizeof(max_align_t);
gNextBlock = newBlock;
}
extern "C"
{
void abort()
{
tty::write("Abort called!");
__asm__ volatile("hlt");
while(true) {};
__builtin_unreachable();
}
void* malloc(size_t size) noexcept
{
if (size == 0)
{
return nullptr;
}
const size_t requiredElements = (size + sizeof(max_align_t) - 1) / sizeof(max_align_t) + 1;
MallocBlock* prevBlock = nullptr;
for (MallocBlock* block = gNextBlock; block != nullptr; block = block->nextBlock)
{
if (block->elements >= requiredElements)
{
MallocBlock* newBlock = nullptr;
if (block->elements > requiredElements)
{
newBlock = reinterpret_cast<MallocBlock*>(reinterpret_cast<max_align_t*>(block) + requiredElements);
newBlock->nextBlock = block->nextBlock;
newBlock->elements = block->elements - requiredElements;
}
else
{
newBlock = block->nextBlock;
}
if (prevBlock != nullptr)
{
prevBlock->nextBlock = newBlock;
}
AllocInfo* allocInfo = reinterpret_cast<AllocInfo*>(block);
allocInfo->elements = requiredElements;
return reinterpret_cast<max_align_t*>(block) + 1;
}
prevBlock = block;
}
return nullptr;
}
void free(void* memory) noexcept
{
if (memory == nullptr)
{
return;
}
MallocBlock* block = reinterpret_cast<MallocBlock*>(static_cast<max_align_t*>(memory) - 1);
block->nextBlock = gNextBlock;
gNextBlock = block;
}
} // extern "C"

65
targets/_any/src/cstdlib/string.cpp Normal file
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#include <string.h>
#include <stdint.h>
extern "C"
{
int memcmp(const void* lhs, const void* rhs, size_t count) noexcept
{
for (size_t pos = 0; pos < count; ++pos)
{
const unsigned char left = *(static_cast<const unsigned char*>(lhs) + pos);
const unsigned char right = *(static_cast<const unsigned char*>(rhs) + pos);
if (left != right) {
return left - right;
}
}
return 0;
}
void memcpy(void* dest, const void* src, size_t count) noexcept
{
for (size_t pos = 0; pos < count; ++pos)
{
*(static_cast<uint8_t*>(dest) + pos) = *(static_cast<const uint8_t*>(src) + pos);
}
}
void memmove(void* dest, const void* src, size_t count) noexcept
{
if (dest < src)
{
for (size_t pos = 0; pos < count; ++pos)
{
*(static_cast<uint8_t*>(dest) + pos) = *(static_cast<const uint8_t*>(src) + pos);
}
}
else
{
for (size_t pos = 0; pos < count; ++pos)
{
*(static_cast<uint8_t*>(dest) + count - pos - 1) = *(static_cast<const uint8_t*>(src) + count - pos - 1);
}
}
}
void* memset(void* dest, int value, size_t count) noexcept
{
for (size_t pos = 0; pos < count; ++pos)
{
*(static_cast<unsigned char*>(dest) + pos) = static_cast<unsigned char>(value);
}
return dest;
}
size_t strlen(const char* str) noexcept
{
size_t len = 0;
while (str[len] != '\0') {
++len;
}
return len;
}
}

26
targets/_any/src/os/panic.cpp Normal file
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#include "os/panic.hpp"
#include <stdarg.h>
#include <cstdio>
#include <cstdlib>
#include "os/tty.hpp"
void panic(const char* message) noexcept
{
tty::write("Kernel panic!\n");
tty::write(message);
tty::putChar('\n');
std::abort();
}
void panicf(const char* format, ...) noexcept
{
tty::write("Kernel panic!\n");
va_list parameters;
va_start(parameters, format);
std::vprintf(format, parameters);
va_end(parameters);
tty::putChar('\n');
std::abort();
}

93
targets/_any/src/os/tty.cpp Normal file
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#include "os/tty.hpp"
#include <cstring>
namespace tty
{
namespace
{
inline const size_t VGA_WIDTH = 80;
inline const size_t VGA_HEIGHT = 25;
size_t gTerminalRow = 0;
size_t gTerminalColumn = 0;
VgaDoubleColor gTerminalColor = VgaDoubleColor();
uint16_t* gTerminalBuffer = reinterpret_cast<uint16_t*>(0xB8000);
constexpr uint8_t vgaEntryColor(VgaDoubleColor color)
{
return static_cast<uint8_t>(color.foreground) | static_cast<uint8_t>(color.background) << 4;
}
constexpr uint16_t vgaEntry(const unsigned char chr, const VgaDoubleColor color)
{
return static_cast<uint16_t>(chr) | static_cast<uint16_t>(vgaEntryColor(color) << 8);
}
void newline()
{
gTerminalColumn = 0;
if (gTerminalRow < VGA_HEIGHT - 1)
{
++gTerminalRow;
}
else
{
// scrolling up
std::memmove(&gTerminalBuffer[0], &gTerminalBuffer[VGA_WIDTH], VGA_WIDTH * (VGA_HEIGHT - 1) * sizeof(uint16_t));
}
}
}
void initialize()
{
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;
gTerminalBuffer[index] = vgaEntry(' ', gTerminalColor);
}
}
}
void setColor(VgaDoubleColor color)
{
gTerminalColor = color;
}
void putEntryAt(char chr, VgaDoubleColor color, size_t posX, size_t posY)
{
const size_t index = posY * VGA_WIDTH + posX;
gTerminalBuffer[index] = vgaEntry(chr, color);
}
void putChar(char chr)
{
if (chr == '\n')
{
newline();
return;
}
putEntryAt(chr, gTerminalColor, gTerminalColumn, gTerminalRow);
if (++gTerminalColumn == VGA_WIDTH)
{
newline();
}
}
void write(const char* data, size_t size)
{
for (size_t idx = 0; idx < size; idx++)
{
putChar(data[idx]);
}
}
void write(const char* data)
{
write(data, std::strlen(data));
}
}

31
targets/i686/SConscript Normal file
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Import('env')
env['AS'] = 'i686-elf-as'
env['CC'] = 'i686-elf-gcc'
env['CXX'] = 'i686-elf-g++'
env['LD'] = 'i686-elf-g++'
def get_crt_object(name: str) -> str:
import subprocess
cmd = [env['CXX']]
cmd.extend(env['CXXFLAGS'])
cmd.append(f'-print-file-name={name}')
result = subprocess.run(cmd, stdout=subprocess.PIPE)
return result.stdout.decode('utf-8').strip()
crtbegin_o = get_crt_object('crtbegin.o')
crtend_o = get_crt_object('crtend.o')
crti_o = env.Object('src/crt/crti.s')
crtn_o = env.Object('src/crt/crtn.s')
i686_sources = Split('''
src/kernel/boot.s
src/kernel/startup.cpp
''')
env['LINKCOM'] = env['LINKCOM'].replace('$_LIBFLAGS', f'{crti_o[0].abspath} {crtbegin_o} $_LIBFLAGS {crtend_o} {crtn_o[0].abspath}')
env.Append(KERNEL_SOURCES = [env.File(f) for f in i686_sources])
env.Append(KERNEL_DEPENDENCIES = [crti_o, crtn_o])
Return('env')

16
targets/i686/src/crt/crti.s Normal file
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/* x86 crti.s */
.section .init
.global _init
.type _init, @function
_init:
push %ebp
movl %esp, %ebp
/* gcc will nicely put the contents of crtbegin.o's .init section here. */
.section .fini
.global _fini
.type _fini, @function
_fini:
push %ebp
movl %esp, %ebp
/* gcc will nicely put the contents of crtbegin.o's .fini section here. */

10
targets/i686/src/crt/crtn.s Normal file
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/* x86 crtn.s */
.section .init
/* gcc will nicely put the contents of crtend.o's .init section here. */
popl %ebp
ret
.section .fini
/* gcc will nicely put the contents of crtend.o's .fini section here. */
popl %ebp
ret

79
targets/i686/src/kernel/boot.s Normal file
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// constants for the multiboot header
.set ALIGN, 1<<0 /* align loaded modules on page boundaries */
.set MEMINFO, 1<<1 /* provide memory map */
.set FLAGS, ALIGN | MEMINFO /* this is the Multiboot 'flag' field */
.set MAGIC, 0x1BADB002 /* 'magic number' lets bootloader find the header */
.set CHECKSUM, -(MAGIC + FLAGS) /* checksum of above, to prove we are multiboot */
// the actual multiboot header
.section .multiboot
.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM
// stack section
.section .bss
.align 16
stack_bottom:
.skip 16384 # 16 KiB
stack_top:
// kernel entry point
.section .text
.global _start
.type _start, @function
_start:
/*
The bootloader has loaded us into 32-bit protected mode on a x86
machine. Interrupts are disabled. Paging is disabled. The processor
state is as defined in the multiboot standard. The kernel has full
control of the CPU. The kernel can only make use of hardware features
and any code it provides as part of itself. There's no printf
function, unless the kernel provides its own <stdio.h> header and a
printf implementation. There are no security restrictions, no
safeguards, no debugging mechanisms, only what the kernel provides
itself. It has absolute and complete power over the
machine.
*/
// store the multiboot info
mov %ebx, (gMultibootHeader)
// setup stack
mov $stack_top, %esp
// call the constructors
mov $start_ctors, %ebx
jmp .ctors_loop_end
.ctors_loop_start:
call *(%ebx)
add 4, %ebx
.ctors_loop_end:
cmp $end_ctors, %ebx
jb .ctors_loop_start
// enter high-level kernel
call kernel_main
// // call the destructors
// mov $start_dtors, %ebx
// jmp .dtors_loop_end
//.dtors_loop_start:
// call *(%ebx)
// add 4, %ebx
//.dtors_loop_end:
// cmp $end_dtors, %ebx
// jb .dtors_loop_start
// We are done. Clear interrupts and halt.
cli
.kernel_end:
hlt
jmp .kernel_end
/*
Set the size of the _start symbol to the current location '.' minus its start.
This is useful when debugging or when you implement call tracing.
*/
.size _start, . - _start

274
targets/i686/src/kernel/multiboot.h Normal file
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/* 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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#include "os/tty.hpp"
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include "./multiboot.h"
extern "C" int gKernelEnd;
namespace
{
void initHeapFromMultibootHeader(const uint32_t firstEntryAddr, const size_t bufferLength) noexcept
{
const uint64_t minAddr = reinterpret_cast<uint64_t>(&gKernelEnd);
for (uint32_t addr = firstEntryAddr; addr < firstEntryAddr + bufferLength;)
{
multiboot_memory_map_t entry = *reinterpret_cast<multiboot_memory_map_t*>(addr);
if(entry.type == MULTIBOOT_MEMORY_AVAILABLE)
{
std::printf("Start Addr: %X | Length: %b\n",
static_cast<unsigned>(entry.addr), static_cast<size_t>(entry.len));
// anything before the kernel we ignore
if (entry.addr < minAddr)
{
// if the entire entry is before the kernel, continue
if (entry.addr + entry.len <= minAddr)
{
addr += sizeof(entry.size) + entry.size;
continue;
}
// otherwise shrink it and use the rest
entry.len -= (minAddr - entry.addr);
entry.addr = minAddr;
}
__ba_registerAllocatableMemory(reinterpret_cast<void*>(entry.addr), entry.len);
}
addr += sizeof(entry.size) + entry.size;
}
}
}
extern "C"
{
multiboot_info_t* gMultibootHeader;
void _init();
void _fini();
void main();
void kernel_main()
{
_init();
/* Initialize terminal interface */
tty::initialize();
std::printf("Kernel End: %p\n", &gKernelEnd);
/* Initialize the heap */
assert(gMultibootHeader->flags & MULTIBOOT_INFO_MEM_MAP);
initHeapFromMultibootHeader(gMultibootHeader->mmap_addr, gMultibootHeader->mmap_length);
main();
_fini();
}
} // extern "C"

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Import('env')
env['AS'] = 'x86_64-elf-as'
env['CC'] = 'x86_64-elf-gcc'
env['CXX'] = 'x86_64-elf-g++'
env['LD'] = 'x86_64-elf-g++'
def get_crt_object(name: str) -> str:
import subprocess
cmd = [env['CXX']]
cmd.extend(env['CXXFLAGS'])
cmd.append(f'-print-file-name={name}')
result = subprocess.run(cmd, stdout=subprocess.PIPE)
return result.stdout.decode('utf-8').strip()
crtbegin_o = get_crt_object('crtbegin.o')
crtend_o = get_crt_object('crtend.o')
crti_o = env.Object('src/crt/crti.s')
crtn_o = env.Object('src/crt/crtn.s')
i686_sources = Split('''
src/kernel/boot.s
src/kernel/startup.cpp
''')
env['LINKCOM'] = env['LINKCOM'].replace('$_LIBFLAGS', f'{crti_o[0].abspath} {crtbegin_o} $_LIBFLAGS {crtend_o} {crtn_o[0].abspath}')
env.Append(KERNEL_SOURCES = [env.File(f) for f in i686_sources])
env.Append(KERNEL_DEPENDENCIES = [crti_o, crtn_o])
env.Append(LINKFLAGS = ['-mcmodel=large', '-mno-red-zone', '-mno-mmx', '-mno-sse', '-mno-sse2'])
Return('env')

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/* x86 crti.s */
.section .init
.global _init
.type _init, @function
_init:
push %rbp
movl %esp, %ebp
/* gcc will nicely put the contents of crtbegin.o's .init section here. */
.section .fini
.global _fini
.type _fini, @function
_fini:
push %rbp
movl %esp, %ebp
/* gcc will nicely put the contents of crtbegin.o's .fini section here. */

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/* x86 crtn.s */
.section .init
/* gcc will nicely put the contents of crtend.o's .init section here. */
pop %rbp
ret
.section .fini
/* gcc will nicely put the contents of crtend.o's .fini section here. */
pop %rbp
ret

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// constants for the multiboot header
.set ALIGN, 1<<0 /* align loaded modules on page boundaries */
.set MEMINFO, 1<<1 /* provide memory map */
.set FLAGS, ALIGN | MEMINFO /* this is the Multiboot 'flag' field */
.set MAGIC, 0x1BADB002 /* 'magic number' lets bootloader find the header */
.set CHECKSUM, -(MAGIC + FLAGS) /* checksum of above, to prove we are multiboot */
// the actual multiboot header
.section .multiboot
.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM
// stack section
.section .bss
.align 16
stack_bottom:
.skip 16384 # 16 KiB
stack_top:
// kernel entry point
.section .text
.global _start
.type _start, @function
_start:
/*
The bootloader has loaded us into 32-bit protected mode on a x86
machine. Interrupts are disabled. Paging is disabled. The processor
state is as defined in the multiboot standard. The kernel has full
control of the CPU. The kernel can only make use of hardware features
and any code it provides as part of itself. There's no printf
function, unless the kernel provides its own <stdio.h> header and a
printf implementation. There are no security restrictions, no
safeguards, no debugging mechanisms, only what the kernel provides
itself. It has absolute and complete power over the
machine.
*/
// store the multiboot info
mov %ebx, (gMultibootHeader)
// setup stack
mov $stack_top, %esp
// call the constructors
mov $start_ctors, %ebx
jmp .ctors_loop_end
.ctors_loop_start:
call *(%ebx)
add 4, %ebx
.ctors_loop_end:
cmp $end_ctors, %ebx
jb .ctors_loop_start
// enter high-level kernel
call kernel_main
// // call the destructors
// mov $start_dtors, %ebx
// jmp .dtors_loop_end
//.dtors_loop_start:
// call *(%ebx)
// add 4, %ebx
//.dtors_loop_end:
// cmp $end_dtors, %ebx
// jb .dtors_loop_start
// We are done. Clear interrupts and halt.
cli
.kernel_end:
hlt
jmp .kernel_end
/*
Set the size of the _start symbol to the current location '.' minus its start.
This is useful when debugging or when you implement call tracing.
*/
.size _start, . - _start

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/* 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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#include "os/tty.hpp"
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include "./multiboot.h"
extern "C" int gKernelEnd;
namespace
{
void initHeapFromMultibootHeader(const uint32_t firstEntryAddr, const size_t bufferLength) noexcept
{
const uint64_t minAddr = reinterpret_cast<uint64_t>(&gKernelEnd);
for (uint32_t addr = firstEntryAddr; addr < firstEntryAddr + bufferLength;)
{
multiboot_memory_map_t entry = *reinterpret_cast<multiboot_memory_map_t*>(addr);
if(entry.type == MULTIBOOT_MEMORY_AVAILABLE)
{
std::printf("Start Addr: %X | Length: %b\n",
static_cast<unsigned>(entry.addr), static_cast<size_t>(entry.len));
// anything before the kernel we ignore
if (entry.addr < minAddr)
{
// if the entire entry is before the kernel, continue
if (entry.addr + entry.len <= minAddr)
{
addr += sizeof(entry.size) + entry.size;
continue;
}
// otherwise shrink it and use the rest
entry.len -= (minAddr - entry.addr);
entry.addr = minAddr;
}
__ba_registerAllocatableMemory(reinterpret_cast<void*>(entry.addr), entry.len);
}
addr += sizeof(entry.size) + entry.size;
}
}
}
extern "C"
{
multiboot_info_t* gMultibootHeader;
void _init();
void _fini();
void main();
void kernel_main()
{
_init();
/* Initialize terminal interface */
tty::initialize();
std::printf("Kernel End: %p\n", &gKernelEnd);
/* Initialize the heap */
assert(gMultibootHeader->flags & MULTIBOOT_INFO_MEM_MAP);
initHeapFromMultibootHeader(gMultibootHeader->mmap_addr, gMultibootHeader->mmap_length);
main();
_fini();
}
} // extern "C"