%include "pm.inc"

org	0x8000

jmp LABEL_BEGIN

[SECTION .GDT]
;全局描述符表
; 		 段基址 段界限 		属性
LABEL_GDT:				Descriptor		0,				0,						 0
LABEL_DESC_CODE_32:		Descriptor		0,			 0FFFFFh,		DA_CR | DA_32 | DA_LIMIT_4K		;结构体初始化时只能传入常量
LABEL_DESC_SHOW:		Descriptor	 0B8000h,		 0FFFFFh,			 DA_DRW				;0B8000h是显存地址,设置该数据段属性为可读写
LABEL_DESC_VRAM:		Descriptor	 0,			 0FFFFFh,			 DA_DRWA | DA_LIMIT_4K		;4G显存,为了C语言开发方便,全部设置为可读写
LABEL_DESC_STACK:		Descriptor		0,			 0FFFFFh,		 	 DA_DRWA | DA_32
LABEL_DESC_FONT: 	Descriptor 0, 0FFFFFh, 		 DA_DRW | DA_LIMIT_4K 

;
LABEL_DESC_6:			Descriptor		0,			 0fffffh,					0409Ah
LABEL_DESC_7:			Descriptor		0,			 	0,						0
LABEL_DESC_8:			Descriptor		0,			 	0,						0
LABEL_DESC_9:			Descriptor		0,			 	0,						0
LABEL_DESC_10:			Descriptor		0,			 	0,						0
%rep 5
Descriptor 0, 0, 0
%endrep

GDTLen	EQU	$ - LABEL_GDT
GDTPtr	DW	GDTLen - 1
		DD	0

;选择子
SelectorCode32	EQU LABEL_DESC_CODE_32 	- 	LABEL_GDT
SelectorShow	EQU LABEL_DESC_SHOW 	- 	LABEL_GDT
SelectorStack EQU LABEL_DESC_STACK 	- 	LABEL_GDT
SelectorVram	EQU	LABEL_DESC_VRAM 	- 	LABEL_GDT
SelectorFont EQU LABEL_DESC_FONT 	- 	LABEL_GDT

;中断描述符表
LABEL_IDT:

%rep 32
	Gate SelectorCode32, SpuriousHandler, 0, DA_386IGate
%endrep

.020h:		;对应主8259A芯片IRQ0引脚,控制时钟中断
	Gate SelectorCode32, timerHandler, 0, DA_386IGate
	
.021h:		;对应主8259A芯片IRQ1引脚,控制键盘中断
	Gate SelectorCode32, KeyBoardHandler, 0, DA_386IGate

%rep 10
	Gate SelectorCode32, SpuriousHandler, 0, DA_386IGate
%endrep

.2ch:		;对应从8259A芯片IRQ4引脚,控制鼠标中断
	Gate SelectorCode32, MouseHandler, 0, DA_386IGate

IdtLen	EQU 	$ - LABEL_IDT
IdtPtr DW 	IdtLen - 1
 DD 	0

[SECTION .s16]
[BITS 16]

LABEL_BEGIN:
	mov	ax, cs		;初始化
	mov ds, ax
	mov es, ax
	mov ss, ax
	mov sp, 0100h

;====== 检测内存 ========
ComputeMem:
	mov ebx, 0
	mov di, MemCheckBuf
.loop:
	mov eax, 0E820h			;固定值
	mov ecx, 20				;es:di内存大小为20字节
	mov edx, 0534D4150h		;表示" SMAP"
	int 15h
	jc LABEL_MEM_CHECK_FAIL	;CF=1表示失败
	add di, 20
	inc dword [dwMCRNumber]
	cmp ebx, 0				;ebx在内存检测过程中不能被修改,当ebx为0时表示检测完成
	jne .loop
	jmp LABEL_MEM_CHECK_OK
	
LABEL_MEM_CHECK_FAIL:
	mov dword [dwMCRNumber], 0

;========================

LABEL_MEM_CHECK_OK:
	;对于超级VGA显示卡,我们可用AX=4F02H和下列BX 的值来设置其显示模式
	×ばつ480 256色
	;4103H: ×ばつ600 256色
	;4105H: 1024*768
	;4107H: 1280*1024

	;设置显示器模式
	mov bx, 0x4101			;分辨率更改为640*480
 mov ax, 0x4f02
	;mov al, 0x13			;al×ばつ480 256色
	;mov ah, 0				;ah寄存器的值表示设置显示器模式
	int 0x10				;调用系统中断的显示服务
	
	;起始地址写入byte2,3,4,7
	xor eax, eax			;清零
	mov ax, cs
	shl	eax, 4
	add eax, LABEL_SEG_CODE32
	mov word [LABEL_DESC_CODE_32 + 2], ax
	shr eax, 16
	mov byte [LABEL_DESC_CODE_32 + 4], al
	mov byte [LABEL_DESC_CODE_32 + 7], ah
	
	;设置C语言堆栈区
	;xor eax, eax
	;mov ax, ds
	;shl eax, 4
	;add eax, LABEL_STACK
	;mov word [LABEL_DESC_STACK + 2], ax
	;shr eax, 16
 ;mov byte [LABEL_DESC_STACK + 4], al
 ;mov byte [LABEL_DESC_STACK + 7], ah
	
	xor eax, eax
 mov ax, cs
 shl eax, 4
 add eax, LABEL_SYSTEM_FONT
 mov word [LABEL_DESC_FONT + 2], ax
 shr eax, 16
 mov byte [LABEL_DESC_FONT + 4], al
 mov byte [LABEL_DESC_FONT + 7], ah
	
	xor eax, eax
	mov ax, ds
	shl eax, 4
	add eax, LABEL_GDT
	mov dword [GDTPtr + 2], eax
	
	lgdt [GDTPtr]
	
	cli					;关中断
	
	call init8259A		;初始化8259A控制器
	
	;准备加载IDT
	xor eax, eax
 mov ax, ds
 shl eax, 4
 add eax, LABEL_IDT
 mov dword [IdtPtr + 2], eax
 lidt [IdtPtr]
	 
	in 	al, 92h			;打开A20地址线
	or 	al, 00000010b
	out 92h, al
	
	mov eax, cr0
	or eax, 1
	mov cr0, eax		;设置cr0的PE位为1,进入保护模式

	;jmp dword SelectorCode32:0
	cli
	jmp dword 1 * 8 : 0

init8259A:
 mov al, 011h		;向主8259A 20h端口发送ICW1,00010001b,表示需要发送ICW4,级联,8字节中断向量,边沿触发
 out 020h, al		
 call io_delay
 
 out 0A0h, al		;向从8259A a0h端口发送ICW1,00010001b,含义同上
 call io_delay

 mov al, 020h		;向主8259A 21h端口发送ICW2,00100000b,表示IR0中断向量为20h
 out 021h, al
 call io_delay

 mov al, 028h		;向从8259A a1h端口发送ICW2,00101000b,表示IR0中断向量为28h
 out 0A1h, al
 call io_delay

 mov al, 04h		;向主8259A 21h端口发送ICW3,00000100b,表示主8259A通过IR2引脚连接到从8259A
 out 021h, al
 call io_delay

 mov al, 02h		;向从8259A a1h端口发送ICW3,00000010b,表示从8259A是连接到主8259A的IR2引脚
 out 0A1h, al
 call io_delay

 mov al, 01h		;向主8259A 21h端口发送ICW4,00000001b,表示当前架构为80x86,非自动EOI(ICW4[1]=0)
 out 021h, al
 call io_delay

 out 0A1h, al		;同上
 call io_delay

 mov al, 11111000b 	;向主8259A发送OCW1,只能写入奇地址端口,允许键盘和时钟中断,打开主8259A控制器的IRQ1和IRQ2号引脚
 out 21h, al
 call io_delay

 mov al, 11101111b	;向从8259A发送OCW1,只能写入奇地址端口,允许鼠标中断,打开从8259A控制器的IRQ4号引脚
 out 0A1h, al
 call io_delay

 ret

io_delay:
 nop
 nop
 nop
 nop
 ret

[SECTION .s32]
[BITS 32]
;初始化C语言栈
LABEL_SEG_CODE32:
	mov ax, SelectorStack
 mov ss, ax
 mov esp, 4096		;change

 mov ax, SelectorVram
 mov ds, ax
	
	mov ax, SelectorShow
	mov gs, ax
	cli

	%include "ckernel.asm"
	
	jmp $
	
;=============================== 中断处理函数 ======================================
_SpuriousHandler:
SpuriousHandler equ _SpuriousHandler - $$	
	iretd

;键盘中断处理函数
_KeyBoardHandler:
KeyBoardHandler equ _KeyBoardHandler - $$
	push es					;保护现场
	push ds
	pushad					;将eax,ebx等所有的32位通用寄存器压入堆栈
	mov eax, esp
	push eax
	
	call intHandlerFromC
	
	pop eax
	mov esp, eax
	popad
	pop ds
	pop es
	iretd


;键盘中断处理函数
_MouseHandler:
MouseHandler equ _MouseHandler - $$
	push es					;保护现场
	push ds
	pushad					;将eax,ebx等所有的32位通用寄存器压入堆栈
	mov eax, esp
	push eax
	
	call intHandlerForMouse
	
	pop eax
	mov esp, eax
	popad
	pop ds
	pop es
	iretd
	
;时钟中断处理函数
_timerHandler:
timerHandler equ _timerHandler - $$
	pushad
	push es
	push ds
	push fs
	push gs
	
	call intHandlerForTimer
	
	pop gs
	pop fs
	pop ds
	pop es
	popad
	iretd

;===================================================================================
get_font_data:
 mov ax, SelectorFont
 mov es, ax
 xor edi, edi
 mov edi, [esp + 4] ;char
 shl edi, 4
 add edi, [esp + 8]
 xor eax, eax
 mov al, byte [es:edi]
 ret

io_hlt: 					;void io_hlt(void);
 HLT
 RET

;关中断,实际上是将标志寄存器第9位的值置0
io_cli:
	CLI
	RET
	
io_sti:
	STI
	RET
	
io_stihlt:
	STI
	HLT
	RET

;从指定的端口dx读入一个8位的数值存入al	
io_in8:
	mov edx, [esp + 4]
	mov eax, 0
	in al, dx
	ret
	
;从指定的端口dx读入一个16位的数值存入ax
io_in16:
	mov edx, [esp + 4]
	mov eax, 0
	in ax, dx
	ret

;从指定的端口dx读入一个32位的数值存入eax
io_in32:
	mov edx, [esp + 4]
	in eax, dx
	ret

;将al的值写入dx表示的端口中
io_out8:
 mov edx, [esp + 4]
 mov al, [esp + 8]
 out dx, al
 ret

;写端口16位数
io_out16:
	mov edx, [esp + 4]
	mov eax, [esp + 8]
	out dx, ax
	ret

;写端口32位数
io_out32:
 mov edx, [esp + 4]
 mov eax, [esp + 8]
 out dx, eax
 ret

;读取标志寄存器的值
io_load_eflags:
	pushfd
	pop eax
	ret

;写入标志寄存器
io_store_eflags:
	mov eax, [esp + 4]
	push eax
	popfd
	ret
	
;导出到C语言的接口,返回写入的地址范围描述符个数
get_memory_block_count:
	mov eax, [dwMCRNumber]		;函数返回值一般存放在eax中
	ret

;导出到C语言的接口,返回地址范围描述符缓冲区地址
get_addr_buffer:
	mov eax, MemCheckBuf
	ret

get_addr_buffer_int:
	mov eax, MemCheckBuf
	ret

;导出到C语言的接口,返回全局描述符表首地址
get_addr_gdt:
 mov eax, LABEL_GDT
 ret

;导出到C语言的接口,返回代码段首地址
get_code32_addr:
 mov eax, LABEL_SEG_CODE32
 ret

;导出到C语言的接口,装载任务状态段寄存器TR
load_tr:
 LTR [esp + 4]
 ret

taskswitch6:
 jmp 6*8:0
 ret

taskswitch7:
 jmp 7*8:0
 ret

taskswitch8:
 jmp 8*8:0
 ret

taskswitch9:
 jmp 9*8:0
 ret
farjmp:
	jmp FAR [esp + 4]			;写入eip
	ret

SegCode32Len equ $ - LABEL_SEG_CODE32

[SECTION .data]
ALIGN 32
[BITS 32]

MemCheckBuf: times 256 db 0
dwMCRNumber: dd 0				;记录BIOS总共向内存中写入多少个数据结构

LABEL_SYSTEM_FONT:
%include "fontData.inc"
SystemFontLength equ $ - LABEL_SYSTEM_FONT		;导入字体二进制数据

[SECTION .gs]
ALIGN 32
[BITS 32]
LABEL_STACK: 
times 512 db 0
TopOfStack1 		equ $ - LABEL_STACK
times 512 db 0
TopOfStack2 		equ $ - LABEL_STACK
LenOfStackSection equ $ - LABEL_STACK