93 lines
2.4 KiB
ArmAsm
93 lines
2.4 KiB
ArmAsm
/*
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Copyright 2025 Kamil Kowalczyk
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Redistribution and use in source and binary forms, with or
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without modification, are permitted provided that the following
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conditions are met:
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1. 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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2. 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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3. Neither the name of the copyright holder nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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“AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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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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*/
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#define FLAGS ((1<<0) | (1<<1))
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#define MAGIC (0x1BADB002)
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#define CHECKSUM (-(MAGIC + FLAGS))
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#define VIRT_BASE 0xC0000000
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.section .multiboot, "aw"
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.align 4
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.long MAGIC
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.long FLAGS
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.long CHECKSUM
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.section .bss
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.align 16
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__stack_bottom:
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.skip 8192
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__stack_top:
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.section .boot, "ax"
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.global _start
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_start:
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movl $(__init_pd - VIRT_BASE), %ecx
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movl %ecx, %cr3
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movl %cr4, %ecx
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orl $0x10, %ecx
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movl %ecx, %cr4
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movl %cr0, %ecx
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orl $0x80000000, %ecx
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movl %ecx, %cr0
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movl $__kernel_higherhalf, %ecx
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jmp *%ecx
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.section .text, "ax"
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__kernel_higherhalf:
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mov $__stack_top, %esp
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push %ebx
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xorl %ebp, %ebp
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call bootmain
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1:
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hlt
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jmp 1b
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.section .data
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.align 4096
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.global __init_pd
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__init_pd:
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.long 0b10000011
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.rept 768-1
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.long 0
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.endr
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.long (0 << 22) | 0b10000011
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.long (1 << 22) | 0b10000011
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.long (2 << 22) | 0b10000011
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.long (3 << 22) | 0b10000011
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.rept 256-4
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.long 0
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.endr
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