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[mike@pc-00065 kernel3]$ gcc -c kernel.c -o kernel.o
[mike@pc-00065 kernel3]$ nasm -f aout k_entry.asm -o k_entry.o
[mike@pc-00065 kernel3]$ ld -T kernel.ld  k_entry.o kernel.o
k_entry.o(.text+0x16):k_entry.o: undefined reference to `_k_main'

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[BITS 32]

[global start]
[extern _k_main] ; this is in the c file

start:
  ; stop using bootloader GDT, and load new GDT
  lgdt [gdt_ptr]

  mov ax,LINEAR_DATA_SEL
  mov ds,ax
  mov es,ax
  mov ss,ax
  mov fs,ax
  mov gs,ax

  call _k_main

  jmp $ ; crash

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void k_main(void) // like main
{
   k_clear_screen();

   k_printf("Welcome to Simplified OS.", 0);
   update_cursor(1, 0);
   k_printf("Right now the kernel is loaded at 1MB physical,/nbut mapped at FF800000 hex.", 3);
   update_cursor(5, 0);

   k_printf("Remapping the PIC...", 6);
   update_cursor(7,0);
   remap_pics(0x20, 0x28);   // irq 0 20h irq 8 28h

   k_printf("PIC remapped starting at 20 hex.", 7);
   update_cursor(8,0);
};

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#! /bin/bash

gcc -c kernel.c -o kernel.o
nasm -f elf k_entry.asm -o k_entry.o
ld -T kernel.ld k_entry.o kernel.o
mv a.out kernel.bin