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/* Copyright (c) 2026 Arslaan Pathan
This software is licensed under the ARPL. See LICENSE for details. */
/* Multiboot header dark magic, do not touch */
.set ALIGN, 1<<0
.set MEMINFO, 1<<1
.set VIDMODE, 1<<2
.set FLAGS, ALIGN | MEMINFO | VIDMODE
.set MAGIC, 0x1BADB002
.set CHECKSUM, -(MAGIC + FLAGS)
/* ask grub for framebuffer
if this breaks the OS i might crash out */
/* THIS IS NOT GUARANTEED 1024x768x32!!!!!
VIDEO MODE **CAN** AND MOST LIKELY WILL CHANGE ON OTHER SYSTEMS!! */
.set WIDTH, 1024
.set HEIGHT, 768
.set DEPTH, 32
.section .multiboot
.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM
.long 0 /* header_addr (unused) */
.long 0 /* load_addr (unused) */
.long 0 /* load_end_addr (unused) */
.long 0 /* bss_end_addr (unused) */
.long 0 /* entry_addr (unused) */
.long 0 /* mode_type: 0 = linear framebuffer */
.long WIDTH /* width */
.long HEIGHT /* height */
.long DEPTH /* depth */
/* Multiboot does not define the esp/stack, create the stack ourselves */
.section bss
/* Stack on x86 must be 16-byte aligned by the System V ABI standard */
.align 16
/* Create a symbol at the bottom, allocate 16KiB, then finally create a symbol at the top */
stack_bottom:
.skip 16384
stack_top:
/* _start is the entrypoint */
.section .text
.global _start
.type _start, @function
_start:
/* we are in 32bit protected mode
interrupts disabled, paging disabled
kernel has full control over cpu */
/* setup the stack, point to the top becausei t grows downwrad on x86 for som e reason */
mov $stack_top, %esp
/* here we need to init crucial processor state.
load the gdt, enable pages, init isa extensions/floating point instructions and stuff
for now just dont do anything we'll add that later(TM) */
/* enter the high level kernel
ABI says we need 16-byte alignment here, we aligned that before and pushed a multiple of 16 bits (zero) so we fine
but i will realign for good measure anyway */
.align 16
push %ebx
call kernel_main
/* if nothing left then just infinite loop */
/*
1. disable interrupts with cli/clear interrupts
2. wait for next interrupt with hlt. because they disabled this will just lockup the ocmputer
3. justincase it wakes up just jmp back to the hlt instruction
*/
cli
1: hlt
jmp 1b
/* set the size of the _start symbol to the current location (.) minus it's _start
for debugging stuff */
.size _start, . - _start
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