154 lines
2.7 KiB
NASM
154 lines
2.7 KiB
NASM
section .data
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global io_hlt, io_cli, io_sti, io_stihlt
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global io_in8, io_in16, io_in32
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global io_out8, io_out16, io_out32
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global io_load_eflags, io_store_eflags
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global load_gdtr, load_idtr
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global tss_flush, gdt_flush, switch_to
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section .text
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switch_to:
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mov eax, [esp+4]
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mov [eax+0], esp
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mov [eax+4], ebp
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mov [eax+8], ebx
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mov [eax+12], esi
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mov [eax+16], edi
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pushf
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pop ecx
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mov [eax+20], ecx
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mov eax, [esp+8]
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mov esp, [eax+0]
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mov ebp, [eax+4]
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mov ebx, [eax+8]
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mov esi, [eax+12]
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mov edi, [eax+16]
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mov eax, [eax+20]
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push eax
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popf
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ret
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[global inw]
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inw:
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xor eax, eax
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push dx
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mov dx, [esp + 4]
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in ax, dx
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pop dx
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ret
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[global read_port]
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read_port:
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mov edx, [esp + 4]
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in al, dx
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ret
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[global idt_flush]
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idt_flush: ; void idt_flush(uint32_t);
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mov eax, [esp + 4]
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lidt [eax]
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ret
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[global gdt_flush]
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gdt_flush: ; void gdt_flush(uint32_t gdtr);
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mov eax, [esp + 4] ; [esp+4]按规定是第一个参数，即gdtr
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lgdt [eax] ; 加载新gdt指针，传入的是地址
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mov ax, 0x10 ; 新数据段
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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 ; 各数据段全部划给这一数据段
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jmp 0x08:.flush ; cs没法mov，只能用farjmp/farcall，这里用farjmp刷新cs
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.flush:
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ret ; 刷新完毕，返回
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tss_flush:
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mov ax, 0x2B
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ltr ax
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ret
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io_hlt: ; void io_hlt(void);
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HLT
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RET
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io_cli: ; void io_cli(void);
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CLI
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RET
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io_sti: ; void io_sti(void);
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STI
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RET
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io_stihlt: ; void io_stihlt(void);
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STI
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HLT
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RET
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io_in8: ; int io_in8(int port);
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MOV EDX,[ESP+4] ; port
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MOV EAX,0
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IN AL,DX
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RET
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io_in16: ; int io_in16(int port);
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MOV EDX,[ESP+4] ; port
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MOV EAX,0
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IN AX,DX
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RET
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io_in32: ; int io_in32(int port);
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MOV EDX,[ESP+4] ; port
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IN EAX,DX
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RET
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io_out8: ; void io_out8(int port, int util);
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MOV EDX,[ESP+4] ; port
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MOV AL,[ESP+8] ; util
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OUT DX,AL
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RET
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io_out16: ; void io_out16(int port, int util);
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MOV EDX,[ESP+4] ; port
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MOV EAX,[ESP+8] ; util
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OUT DX,AX
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RET
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io_out32: ; void io_out32(int port, int util);
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MOV EDX,[ESP+4] ; port
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MOV EAX,[ESP+8] ; util
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OUT DX,EAX
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RET
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io_load_eflags: ; int io_load_eflags(void);
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PUSHFD ; PUSH EFLAGS
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POP EAX
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RET
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io_store_eflags: ; void io_store_eflags(int eflags);
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MOV EAX,[ESP+4]
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PUSH EAX
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POPFD ; POP EFLAGS
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RET
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load_gdtr: ; void load_gdtr(int limit, int addr);
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MOV AX,[ESP+4] ; limit
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MOV [ESP+6],AX
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LGDT [ESP+6]
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RET
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load_idtr: ; void load_idtr(int limit, int addr);
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MOV AX,[ESP+4] ; limit
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MOV [ESP+6],AX
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LIDT [ESP+6]
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RET |