forked from KolibriOS/kolibrios
66 lines
2.0 KiB
PHP
66 lines
2.0 KiB
PHP
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; ;;
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;; SWITCH TO 32 BIT PROTECTED MODE ;;
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;; ;;
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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os_data = os_data_l-gdts ; GDTs
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os_code = os_code_l-gdts
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int_code equ int_code_l-gdts
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int_data equ int_data_l-gdts
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tss0sys equ tss0sys_l-gdts
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graph_data equ 3+graph_data_l-gdts
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tss0 equ tss0_l-gdts
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app_code equ 3+app_code_l-gdts
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app_data equ 3+app_data_l-gdts
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; CR0 Flags - Protected mode and Paging
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mov ecx, CR0_PE
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; Enabling 32 bit protected mode
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sidt [cs:old_ints_h-0x10000]
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cli ; disable all irqs
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cld
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mov al,255 ; mask all irqs
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out 0xa1,al
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out 0x21,al
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l.5: in al, 0x64 ; Enable A20
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test al, 2
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jnz l.5
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mov al, 0xD1
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out 0x64, al
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l.6: in al, 0x64
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test al, 2
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jnz l.6
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mov al, 0xDF
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out 0x60, al
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l.7: in al, 0x64
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test al, 2
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jnz l.7
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mov al, 0xFF
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out 0x64, al
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lgdt [cs:gdts-0x10000] ; Load GDT
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mov eax, cr0 ; Turn on paging // protected mode
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or eax, ecx
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and eax, 10011111b *65536*256 + 0xffffff ; caching enabled
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mov cr0, eax
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jmp $+2
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org $+0x10000
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mov ax,os_data ; Selector for os
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mov ds,ax
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mov es,ax
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mov fs,ax
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mov gs,ax
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mov ss,ax
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mov esp,0x3ec00 ; Set stack
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jmp pword os_code:B32 ; jmp to enable 32 bit mode
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if gdte >= $
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error 'GDT overlaps with used code!'
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end if
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