102 lines
3.6 KiB
NASM
102 lines
3.6 KiB
NASM
;
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; Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
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; All rights reserved.
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;
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; Redistribution and use in source and binary forms, with or without
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; modification, are permitted provided that the following conditions are met:
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; * Redistributions of source code must retain the above copyright
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; notice, this list of conditions and the following disclaimer.
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; * Redistributions in binary form must reproduce the above copyright
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; notice, this list of conditions and the following disclaimer in the
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; documentation and/or other materials provided with the distribution.
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; * Neither the name of the University nor the names of its contributors
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; may be used to endorse or promote products derived from this software
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; without specific prior written permission.
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;
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; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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; ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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; DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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; DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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; (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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; ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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[BITS 32]
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; We use a special name to map this section at the begin of our kernel
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; => Multiboot needs its magic number at the begin of the kernel
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SECTION .mboot
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global start
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start:
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jmp stublet
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; This part MUST be 4byte aligned, so we solve that issue using 'ALIGN 4'
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ALIGN 4
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mboot:
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; Multiboot macros to make a few lines more readable later
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MULTIBOOT_PAGE_ALIGN equ 1<<0
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MULTIBOOT_MEMORY_INFO equ 1<<1
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; MULTIBOOT_AOUT_KLUDGE equ 1<<16
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MULTIBOOT_HEADER_MAGIC equ 0x1BADB002
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MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO ; | MULTIBOOT_AOUT_KLUDGE
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MULTIBOOT_CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
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EXTERN code, bss, end
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; This is the GRUB Multiboot header. A boot signature
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dd MULTIBOOT_HEADER_MAGIC
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dd MULTIBOOT_HEADER_FLAGS
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dd MULTIBOOT_CHECKSUM
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; AOUT kludge - must be physical addresses. Make a note of these:
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; The linker script fills in the data for these ones!
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; dd mboot
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; dd code
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; dd bss
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; dd end
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; dd start
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SECTION .text
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ALIGN 4
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stublet:
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; initialize stack pointer.
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mov esp, default_stack_pointer
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; initialize cpu features
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call cpu_init
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; interpret multiboot information
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extern multiboot_init
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push ebx
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call multiboot_init
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add esp, 4
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; jump to the boot processors's C code
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extern main
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call main
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jmp $
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global cpu_init
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cpu_init:
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mov eax, cr0
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; enable caching, disable paging and fpu emulation
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and eax, 0x1ffffffb
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; ...and turn on FPU exceptions
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or eax, 0x22
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mov cr0, eax
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; clears the current pgd entry
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xor eax, eax
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mov cr3, eax
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; at this stage, we disable the SSE support
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mov eax, cr4
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and eax, 0xfffbf9ff
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mov cr4, eax
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ret
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; Here is the definition of our stack. Remember that a stack actually grows
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; downwards, so we declare the size of the data before declaring
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; the identifier 'default_stack_pointer'
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SECTION .data
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resb 8192 ; This reserves 8KBytes of memory here
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default_stack_pointer:
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SECTION .note.GNU-stack noalloc noexec nowrite progbits
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