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Small optimizations #6

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Small optimizations #6

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062465d
Small optimizations in the 6th tutorial source
BeanieMen Sep 5, 2022
dc3ec32
Sorry for that, i am new to github
BeanieMen Sep 5, 2022
253d913
Small optimization
BeanieMen Sep 5, 2022
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22 changes: 12 additions & 10 deletions 6/6.asm
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Original file line number Diff line number Diff line change
@@ -1,23 +1,23 @@
[org 0x7c00]


mov [BOOT_DISK], dl



; defines the constant code and data segments
CODE_SEG equ GDT_code - GDT_start
DATA_SEG equ GDT_data - GDT_start

cli
lgdt [GDT_descriptor]

mov eax, cr0
or eax, 1
mov cr0, eax


; far jump to our labe;
jmp CODE_SEG:start_protected_mode

jmp $


jmp $

GDT_start: ; must be at the end of real mode code
GDT_null:
dd 0x0
Expand All @@ -42,8 +42,8 @@ GDT_start: ; must be at the end of real mode code
GDT_end:

GDT_descriptor:
dw GDT_end - GDT_start - 1
dd GDT_start
dw GDT_end - GDT_start - 1 ; size
dd GDT_start ; location


[bits 32]
Expand All @@ -53,7 +53,9 @@ start_protected_mode:
mov [0xb8000], ax
jmp $

BOOT_DISK: db 0

times 510-($-$$) db 0
dw 0xaa55