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authorAqua-sama <aqua@iserlohn-fortress.net>2021-02-07 11:36:04 +0200
committerAqua-sama <aqua@iserlohn-fortress.net>2021-02-07 11:36:04 +0200
commit21e7874d9a9729b3ac7520a0a7ef8f7f5bc7601b (patch)
tree40df2b6564739d7ec1e67468fd3b8e628eb83bc7 /boot.s
parentlibk: add some tests (diff)
downloadkernel.cpp-21e7874d9a9729b3ac7520a0a7ef8f7f5bc7601b.tar.xz
Rewrite makefile
Diffstat (limited to 'boot.s')
-rw-r--r--boot.s93
1 files changed, 0 insertions, 93 deletions
diff --git a/boot.s b/boot.s
deleted file mode 100644
index bb446d8..0000000
--- a/boot.s
+++ /dev/null
@@ -1,93 +0,0 @@
-/*
- Declare a multiboot header that marks the program as a kernel.
- https://www.gnu.org/software/grub/manual/multiboot2/html_node/index.html
-
- The Multiboot2 header must be contained completely within the first
- 32kB of the OS image, and must be 64-bit (8 byte) aligned.
-*/
-.set MULTIBOOT_HEADER_MAGIC, 0xe85250d6 # multiboot2 magic number
-.set MULTIBOOT_ARCHITECTURE, 0 # protected mode i386
-.set MULTIBOOT_HEADER_TAG_END, 0
-
-.section .multiboot
-.align 8
-header_start:
- .int MULTIBOOT_HEADER_MAGIC
- .int MULTIBOOT_ARCHITECTURE
- .int header_end - header_start
- .int -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_ARCHITECTURE + (header_end - header_start))
-
- # TODO tags go here
-
- .short MULTIBOOT_HEADER_TAG_END
- .short 0
- .int 8
-header_end:
-
-/*
- The stack on x86 must be 16-byte aligned according to the System V ABI
- standard and de-facto extensions. The compiler will assume the stack is
- properly aligned and failure to align the stack will result in undefined
- behavior.
-*/
-.section .stack, "aw", @nobits
-.align 16
-stack_bottom:
- .skip 16 * 1024
-stack_top:
-
-/*
- The linker script specifies _start as the entry point to the kernel and the
- bootloader will jump to this position once the kernel has been loaded.
-*/
-.section .text
-.global _start
-.type _start, @function
-_start:
- mov $stack_top, %esp # point the stack pointer to the stack
-
- /*
- This is a good place to initialize crucial processor state before the
- high-level kernel is entered. It's best to minimize the early
- environment where crucial features are offline. Note that the
- processor is not fully initialized yet: Features such as floating
- point instructions and instruction set extensions are not initialized
- yet. The GDT should be loaded here. Paging should be enabled here.
- C++ features such as global constructors and exceptions will require
- runtime support to work as well.
- */
-
- pushl %ebx # push the pointer to the multiboot structure
- pushl %eax # push the multiboot magic value
-
- /*
- Enter the high-level kernel. The ABI requires the stack is 16-byte
- aligned at the time of the call instruction (which afterwards pushes
- the return pointer of size 4 bytes). The stack was originally 16-byte
- aligned above and we've pushed a multiple of 16 bytes to the
- stack since (pushed 0 bytes so far), so the alignment has thus been
- preserved and the call is well defined.
- */
- call kernel_main
-
- /*
- If the system has nothing more to do, put the computer into an
- infinite loop. To do that:
- 1) Disable interrupts with cli (clear interrupt enable in eflags).
- They are already disabled by the bootloader, so this is not needed.
- Mind that you might later enable interrupts and return from
- kernel_main (which is sort of nonsensical to do).
- 2) Wait for the next interrupt to arrive with hlt (halt instruction).
- Since they are disabled, this will lock up the computer.
- 3) Jump to the hlt instruction if it ever wakes up due to a
- non-maskable interrupt occurring or due to system management mode.
- */
- cli
-hang: hlt
- jmp hang
-
-/*
-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