44 lines
903 B
NASM
44 lines
903 B
NASM
; since we have no stack we have to create one for the OS
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global loader
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; this section is partly handled by nasm tolerating some minor bs
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MAGIC_NUMBER equ 0x1BADB002
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FLAGS equ 0x0
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CHECKSUM equ -MAGIC_NUMBER
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; size in bytes of stack
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KERNEL_STACK_SIZE equ 4096
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extern test_fb
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section .text
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; align all instructions to 4 byte boundary by the x86 instruction set law
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align 4
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; dropping our magic and other things into memory
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dd MAGIC_NUMBER
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dd FLAGS
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dd CHECKSUM
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loader:
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mov al, 14
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mov dx, 0x3d4
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out dx, al ; 14 tells the framebuffer to expect the highest 8 bits of the position
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mov al, 0
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mov dx, 0x3d5
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out dx, al ; sending the highest 8 bits of 0x0050
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mov al, 15
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mov dx, 0x3d4
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out dx, al ; 15 tells the framebuffer to expect the lowest 8 bits of the position
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mov al, 0
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mov dx, 0x3d5
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out dx, al ; sending the lowest 8 bits of 0x0050
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call test_fb
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.loop:
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jmp .loop
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