kernel32.asm

来自「TestOS - 带简单GUI的DOS扩展OS// 源代码// ASM// 英文」· 汇编 代码 · 共 161 行

;=========================================================;
; Real/Pmode                                     11/12/03 ;
;---------------------------------------------------------;
; DOS EXTREME OS V0.01                                    ;
; by Craig Bamford.                                       ;
;                                                         ;
; fasm pm os test EXE program  (DOS EXTREME)              ;
; fasm pm.asm pm.exe                                      ;
;                                                         ;                      
; Thanks to: Tomasz Grysztar,Christopher Giese            ;
; Alexei A. Frounze, smaffy.                              ;
;                                                         ;
;=========================================================;
format MZ		; code starts at offset 100h
;===============================================================================================;
;	16-bit real mode
;===============================================================================================;
	use16

        jmp   start

include '386.inc'
include "Ata_Atapi16.inc"
include 'A20.inc'
include 'vesa2.inc'  ;*           
start:	
        push  cs
	pop   ds
        push  ds
        pop   es
        call  GetAtaPiDrive
        call  Atapi_Address
        call  enable_A20
        call  vesa    ;*
        xor   ebx,ebx
	mov   bx,ds                                                  ; BX=segment
	shl   ebx,4                                                  ; BX="linear" address of segment base
	mov   eax,ebx
	mov   [sys_code_1 + 2],ax                                    ; set base address of 32-bit segments
	mov   [sys_data_1 + 2],ax
	mov   [Real_code_1 + 2],ax                                   ; set base address of 16-bit segments
	mov   [Real_data_1 + 2],ax
	shr   eax,16
	mov   [sys_code_1 + 4],al
	mov   [sys_data_1 + 4],al
	mov   [Real_code_1 + 4],al
	mov   [Real_data_1 + 4],al

	mov   [sys_code_1 + 7],ah
	mov   [sys_data_1 + 7],ah
	mov   [Real_code_1 + 7],ah
	mov   [Real_data_1 + 7],ah

        add   ebx,gdt		                                  ; EBX=linear address of gdt
	mov   [gdtr + 2],ebx
	add   ebx,idt - gdt	                                  ; EBX=linear address of idt
	mov   [idtr + 2],ebx
        cli

	mov   ax,cs
	mov   [RealModeCS],ax
	

	mov   ax,0xB800
	mov   es,ax

	lgdt  [gdtr]                                               ; VLoad the GDTR with the base address and limit of the GDT
        lidt  [idtr]
	mov   eax,cr0                                              ; Set the PE [protected mode enable] bit in register CR0 
	or    al,1
	mov   cr0,eax
        

	jmp   sys_code:do_pm                                       ; jumps to do_pm


;===============================================================================================;
;	32-bit protected mode
;===============================================================================================;
use32
do_pm:

        xor   edi,edi
        xor   esi,esi

	mov   ax,sys_data
        mov   ds,ax
        mov   ss,ax
        nop
	mov   es,ax
	mov   fs,ax
	mov   gs,ax
	
        mov   ax,linear_sel
	mov   es,ax
      
        jmp   inc_over2
;=======================================;
;	   Include Files.               ;
;=======================================;

        include 'errors.inc'
        include 'msg.inc'
        include 'pic.inc'
        include 'isr.asm'
        include 'keyboard.inc'
        include 'keymaps.inc'
        include 'TextMode.inc'
        include 'TimeDate.inc'
        include 'Fdd.inc'
        include 'CdPlayer.inc'
        include 'vesa2_info.inc'
        include 'Ata_Atapi39.inc'
        include 'VesaGraphics.inc'
;=======================================;
;          Include File End.            ;
;=======================================;

inc_over2:        
	call  remap_pic
        call  unmask_irqs
        call  Fdd_motor_off

;***************************************;
;             Testing Code.             ;
;***************************************;

        call  Cd_player

;***************************************;
;             Testing End.              ;
;***************************************;
nogo: 
        jmp   nogo

;===============================================================================================;
; data
;===============================================================================================;
RealModeIP:
        dw 0

RealModeCS:
	dw 0


;===============================================================================================;
;	global descriptor table (GDT)
;===============================================================================================;
gdtr:	dw gdt_end - gdt - 1	                                  ; GDT limit
	dd gdt                                                    ; (GDT base gets set above)

include 'gdt.asm'
;===============================================================================================;
;	interrupt descriptor table (IDT)
;===============================================================================================;

idtr:	dw idt_end - idt - 1	                                 ; IDT limit
	dd idt	

include 'idt.asm'