Power-Programmierung

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Assembly Source File | 1989-03-20 | 31.5 KB | 658 lines

PAGE ,132 TITLE Protected mode programming .286P ; Privliged programming ;=============================================================================; ; ; ; Example "skeleton" program that creates a GDT, IDT ; ; and enables Protected Mode as follows: ; ; ; ; 1) Provides GDT containing descriptors needed by the initial ; ; Protected Mode Task, ; ; ; ; 2) Provides IDT containing a full complement of gates for CPU ; ; Exceptions and eight 8259A interrupts, ; ; ; ; 3) Enables 80286 Protected Mode. ; ; ; ; This example enables access to the full 16MB physical address space. ; ; It DOES NOT perform task switching. ; ; ; ; Suggested that object code is burned into two 2764 EPROM's ; ;=============================================================================; PAGE Descriptor STRUC ; A descriptor structure Limit Dw ? ; A limit in bytes BaseLowWord Dw ? ; Base word BaseHighByte Db ? ; Base byte high Access Db ? ; Access rights byte Reserved Dw 0 ; Reserved word Descriptor ENDS ; EQUATES GDT_ELEMENTS EQU 16 ; Number of descriptor slots in GDT IDT_ELEMENTS EQU 64 ; Number of slots in IDT MAIN_CODE_SELECTOR EQU 0038h ; Selector for main code segment EX_CODE_SELECTOR EQU 0040h ; Selector for exception code INT_CODE_SELECTOR EQU 0048h ; Selector for interrupt code segment ; Physical mem equates -- This deals with the EPROM's MAIN_CODE_BASE EQU 0068h ; EXCEPTION_CODE_BASE EQU 0078h ; INTERRUPT_CODE_BASE EQU 0088h ; ; I/O address equates OUTPUT_DATA_PORT EQU 03BCh ; Address of Data out of printer OUTPUT_STATUS_PORT1 EQU 03BDh ; Address of control latch (in) OUTPUT_STATUS_PORT2 EQU 03BEh ; Control latch of ptr (out) STROBE_HIGH EQU 0Dh ; STROBE_LOW EQU 0Ch ; PAGE ;=============================================================================; ; Definition of EPROM contents. ; ; This example assumes two 2764 (8K x 8) at high end of memory. ; ; The Lowest address is thus FFC000h. ; ; Since the 80286 CS base initially equals FF0000h, the lowest EPROM ; ; address is referenced by an IP value of C000h. ; ;=============================================================================; ; EPROM RESIDENT IMAGE OF GDT and IDT ; Initlization copies image to RAM, starting at 000000h. INITIAL_DATA SEGMENT ASSUME cs:INITIAL_DATA ; The size of this GDT allows 16 slots for descriptors or gates Gdt_Image_Start: ;---The first GDT slot is always unused (The null selector, SLECTOR - 0000h---; Dw 0 ; Dw 0 ; Dw 0 ; Dw 0 ; ;---GDT_alias descriptor (SELECTOR - 0008h)-----------------------------------; Dw 7Fh ; Limit (16 * 8) - 1 Dw 0 ; Base at 0 Db 0 ; Db 10010011b ; Access rights for data segment Dw 0 ; Insure Compatability with 80386 ;---IDT_alias secriptor (SELECTOR = 0010h)------------------------------------; Dw 1FFh ; IDT_alias limit (64 * 8) - 1 Dw 80h ; Base is after GDT in RAM Db 0 ; Db 10010011b ; Access rights for data segment Dw 0 ; ;---Level 0 stack segment descriptor (SELECTOR = 0018h)-----------------------; Dw TOS - 1 ; Limit 1k (1024 - 1) Dw SEG TOS ; Follows IDT in RAM Db 0 ; Db 10010011b ; Access rights byte Dw 0 ; ;---Main data segment descriptor (SELECTOR - 0020h)---------------------------; Dw 0FFh ; Limit (256 - 1) Dw 680h ; Follows level 0 stack Db 0 ; Db 10010011b ; Access rights byte Dw 0 ; ;---Exception data segment descriptor (SELECTOR = 0028h)----------------------; Dw 0FFh ; Limit (256 -1) Dw 780h ; Base follows main Db 0 ; Db 10010011b ; Access rights byte Dw 0 ; ;---Interrupt data segment descriptor (SELECTOR = 0030h)---------------------; Dw 0FFh ; Limit of interrupt (256 - 1) Dw 880h ; Base after the data segment Db 0 ; Db 10010011b ; Acess rights byte Dw 0 ; Insure compatibility with 80386 ;---Main CODE segment descriptor (SELECTOR = 0038h)---------------------------; Dw End_Of_Main_Code; Limit of main code Dw SEG End_Of_Main_Code ; Base address Db 0 ; Db 10011011b ; Access rights for CODE segment Dw 0 ; ;---Exception CODE segment descriptor (SELECTOR = 0040h)----------------------; Dw End_Of_Exception_Code ; Limit of Excpetion CODE Dw SEG End_Of_Exception_Code Db 0 ; Base address of Excpetion Db 10011011b ; Access rights of CODE Dw 0 ; ;---Interrupt CODE segment Descriptor (SELECTOR = 0048h)----------------------; Dw End_Of_Interrupt_Code ; Limit Dw SEG End_Of_Interrupt_Code Db 0 ; Base address Db 10011011b ; Interrupt Acess of CODE Dw 0 ; ;---Blank Descriptor slots (10-15)--------------------------------------------; Db (16-10)*8 Dup(0) Gdt_Image_End: PAGE Idt_Image_Start: ;=============================================================================; ; IDT image in EPROM to be copied to RAM diring INIT, note gate for each ; ; exception by the 80286, furthurmore, assuming one 8259A int controller, ; ; 8 int gates placed in slots 32-39. ; ; The sixe of this IDT allows 64 slots for gates. ; ;=============================================================================; ;---Divide Error (Exception 0)------------------------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; Acess rights for TRAP gate Dw 0 ; 80386 comp. ;---Single Step (Exception 1)-------------------------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Db 11100111b ; Access rights for TRAP gate Dw 0 ; ;---NMI int (Exception 2)-----------------------------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100110b ; Access rights of INT gate Dw 0 ; ;---Breakpoint trap (Exception 3)---------------------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---INTO trap (Exception 4)---------------------------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---BOUNDS trap (Exception 5)------------------------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---Invalid Opcode (Exception 6)----------------------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---Math coprocessor not available (Exception 7)------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---Double Fault (Exception 8)------------------------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---Coproccessor operand partially beond segment (Exception 9)----------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---Invalid task state segment (Exception 10)---------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---CS, DS, ES segment not present (Exception 11)-----------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---SS not present or stack segment violation (Exception 12)------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---General protection violation (Exception 13)-------------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---Excpetion 14 reserved by intell but not used on 80286---------------------; Dw 0 ; Dw 0 ; Db 0 ; Db 0 ; Access code of 0 = invalid Dw 0 ; ;---Excpetion 15 reserved by intell but not used on 80286---------------------; Dw 0 ; Dw 0 ; Db 0 ; Db 0 ; Access code of 0 = invalid Dw 0 ; ;---Math coprocessor calculation error (Exception 16)-------------------------; Dw End_Of_Exception_Code Dw SEG End_Of_Exception_Code ;; Db 0 ; Base Db 11100111b ; TRAP access Dw 0 ; ;---Exception 17-31 reserved by intel, but unused by 80286--------------------; Db (32-17)*8 Dup(0); Reserve 0 on all slots PAGE ;-----------------------------------------------------------------------------; ; Interrupt gates are placed after intell reserved IDT slots 0-31. ; ; 8 gates for ones generated by 8259A are init for base of 32. ; ;-----------------------------------------------------------------------------; ;---Hardware Interrupt 32-----------------------------------------------------; Dw End_Of_Interrupt_Code Dw SEG End_Of_Interrupt_Code ; Db 0 ; Base Db 11100110b ; Interrupt gate access byte Dw 0 ; 0 for compat with 80386 ;---Hardware Interrupt 33-----------------------------------------------------; Dw End_Of_Interrupt_Code Dw SEG End_Of_Interrupt_Code ; Db 0 ; Base Db 11100110b ; Interrupt gate access byte Dw 0 ; 0 for compat with 80386 ;---Hardware Interrupt 34-----------------------------------------------------; Dw End_Of_Interrupt_Code Dw SEG End_Of_Interrupt_Code ; Db 0 ; Base Db 11100110b ; Interrupt gate access byte Dw 0 ; 0 for compat with 80386 ;---Hardware Interrupt 35-----------------------------------------------------; Dw End_Of_Interrupt_Code Dw SEG End_Of_Interrupt_Code ; Db 0 ; Base Db 11100110b ; Interrupt gate access byte Dw 0 ; 0 for compat with 80386 ;---Hardware Interrupt 36-----------------------------------------------------; Dw End_Of_Interrupt_Code Dw SEG End_Of_Interrupt_Code ; Db 0 ; Base Db 11100110b ; Interrupt gate access byte Dw 0 ; 0 for compat with 80386 ;---Hardware Interrupt 37-----------------------------------------------------; Dw End_Of_Interrupt_Code Dw SEG End_Of_Interrupt_Code ; Db 0 ; Base Db 11100110b ; Interrupt gate access byte Dw 0 ; 0 for compat with 80386 ;---Hardware Interrupt 38-----------------------------------------------------; Dw End_Of_Interrupt_Code Dw SEG End_Of_Interrupt_Code ; Db 0 ; Base Db 11100110b ; Interrupt gate access byte Dw 0 ; 0 for compat with 80386 ;---Hardware Interrupt 39-----------------------------------------------------; Dw End_Of_Interrupt_Code Dw SEG End_Of_Interrupt_Code ; Db 0 ; Base Db 11100110b ; Interrupt gate access byte Dw 0 ; 0 for compat with 80386 ;---IDT slots of interrupts numbered 40-63 are not used but available---------; Db (64-40)*8 Dup (0) Idt_Image_End: INITIAL_DATA ENDS PAGE ;=============================================================================; ; Initialization code -- setup. Made to put system in protected mode. ; ;=============================================================================; MAIN_CODE SEGMENT ASSUME cs:MAIN_CODE ; Jmp Flush ; Jump to flish ; Gdt_Pointer: ; Dw Gdt_Image_End - Gdt_Image_Start - 1 ; Size of GDT area Dw ? ; Location in ram Dw 0 ; ; Idt_Pointer: ; Dw Idt_Image_End - Idt_Image_Start-1 ; Size of IDT Dw ? ; Location Dw 0 ; ; Initialize: ; Jump far to here Push Cs ; First set up the main pointers Push Cs ; So that we can make prot mode Pop Ds ; Possible Pop Es ; Lea Di,Gdt_Pointer ; Get the offset of this Mov Ax,INITIAL_DATA ; Get the segment of this Mov [DI+2],Ax ; Save the segment Lea Di,Idt_Pointer ; Mov [Di+2],Ax ; ; Cli ; Lgdt DWORD PTR cs:Gdt_Pointer ; Load this Lidt DWORD PTR cs:Idt_Pointer ; And this ; Smsw Ax ; Get the machone status word Or Ax,1 ; Set the PE bit Lmsw Ax ; NOW WE ARE IN PROTECTED MODE Jmp Fls ; Clear the queue ; Fls: ; Mov Ax,18h ; Initialize SS:SP (SELECTOR 18h) Mov Ss,Ax ; Mov Sp,400h ; Inital for 1k stack ; ; JMP FAR MAIN_CODE:0 ; To make correct thing ; Db 0EAh ; Far jmp nm Dw 0 ; Dw MAIN_CODE_SELECTOR ; Flush: Sti ; Mov Al,'P' ; Char P Tag: Mov Bx,Ax ; Save Mov Dx,OUTPUT_DATA_PORT Out Dx,Al ; Do this Mov Dx,OUTPUT_STATUS_PORT1 Tl1a: In Al,Dx ; Get the status of printer Test Al,80h ; Check if ready Jz Tl1a ; Mov Dx,OUTPUT_STATUS_PORT2 Mov Al,STROBE_HIGH ; Strobe high Out Dx,Al ; Mov Al,STROBE_LOW ; Strobe low Jmp NextInst ; Delay NextInst: Out Dx,Al ; Cmp Bl,'P' ; First or second time Jne Forever ; Mov Al,0Dh ; Carriage return Jmp Tag ; ; Forever: Jmp Forever ; Entry: Cli ; Jmp Initialize ; End_Of_Main_Code Equ $ ; MAIN_CODE ENDS PAGE ;=============================================================================; ; Exception handler code segment. ; ;=============================================================================; EXCEPTION_CODE SEGMENT Assume Cs:EXCEPTION_CODE Ex_0: ; Push Ax ; Mov Al,0 ; Call Report_Exception; Pop Ax ; Iret ; Ex_1: ; Push Ax ; Save AX Mov Al,1 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return ; -- NMI handled as int ; Ex_3: ; Push Ax ; Save AX Mov Al,3 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_4: ; Push Ax ; Save AX Mov Al,4 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_5: ; Push Ax ; Save AX Mov Al,5 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_6: ; Push Ax ; Save AX Mov Al,6 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_7: ; Push Ax ; Save AX Mov Al,7 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_8: ; Push Ax ; Save AX Mov Al,8 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_9: ; Push Ax ; Save AX Mov Al,9 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_10: ; Push Ax ; Save AX Mov Al,10 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_11: ; Push Ax ; Save AX Mov Al,11 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_12: ; Push Ax ; Save AX Mov Al,12 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return Ex_13: ; Push Ax ; Save AX Mov Al,13 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return ; 80286 will not generate 14,15 Ex_16: ; Push Ax ; Save AX Mov Al,16 ; Put EXP number in Al Call Report_Exception; Report to user Pop Ax ; Get number Iret ; And return ; Expection 17-31 not here Report_Exception: ; Push Ax ; Push Bx ; Push Dx ; ; Tg1: Mov Bx,Ax ; Save the value passed Mov Dx,OUTPUT_DATA_PORT Out Dx,Al ; Do this Mov Dx,OUTPUT_STATUS_PORT1 Xl1a: In Al,Dx ; Get the status of printer Test Al,80h ; Check if ready Jz Xl1a ; Mov Dx,OUTPUT_STATUS_PORT2 Mov Al,STROBE_HIGH ; Strobe high Out Dx,Al ; Mov Al,STROBE_LOW ; Strobe low Jmp NextInst2 ; Delay NextInst2: Out Dx,Al ; Cmp Bl,0Ah ; First or second time or last Je ByBye ; Cmp Bl,0Dh ; Carriage return? Je ThrowLf ; Mov Al,0Dh ; Jmp Tg1 ; ThrowLf: Mov Al,0Ah ; Jmp Tg1 ; ; ByBye: Pop Dx ; Pop Bx ; Pop Ax ; Ret ; End_Of_Exception_Code EQU $ EXCEPTION_CODE ENDS PAGE ;=============================================================================; ; Interrrupt Code Segment. ; ;=============================================================================; INTERRUPT_CODE Segment Assume Cs:INTERRUPT_CODE NMI: ; Push Ax ; Mov Al,2 ; NMI call Call Report_Interrupt; Pop Ax ; Iret ; Int_32: ; Push Ax ; Mov Al,32 ; Place INT in al Call Report_Interrupt; Call to report Pop Ax ; Get Ax Iret ; And Int Return Int_33: ; Push Ax ; Mov Al,33 ; Place INT in al Call Report_Interrupt; Call to report Pop Ax ; Get Ax Iret ; And Int Return Int_34: ; Push Ax ; Mov Al,34 ; Place INT in al Call Report_Interrupt; Call to report Pop Ax ; Get Ax Iret ; And Int Return Int_35: ; Push Ax ; Mov Al,35 ; Place INT in al Call Report_Interrupt; Call to report Pop Ax ; Get Ax Iret ; And Int Return Int_36: ; Push Ax ; Mov Al,36 ; Place INT in al Call Report_Interrupt; Call to report Pop Ax ; Get Ax Iret ; And Int Return Int_37: ; Push Ax ; Mov Al,37 ; Place INT in al Call Report_Interrupt; Call to report Pop Ax ; Get Ax Iret ; And Int Return Int_38: ; Push Ax ; Mov Al,38 ; Place INT in al Call Report_Interrupt; Call to report Pop Ax ; Get Ax Iret ; And Int Return Int_39: ; Push Ax ; Mov Al,39 ; Place INT in al Call Report_Interrupt; Call to report Pop Ax ; Get Ax Iret ; And Int Return ; Report_Interrupt: ; Push Ax ; Push Bx ; Push Dx ; ; Tg2: Mov Bx,Ax ; Save the value passed Mov Dx,OUTPUT_DATA_PORT Out Dx,Al ; Do this Mov Dx,OUTPUT_STATUS_PORT1 Zl1a: In Al,Dx ; Get the status of printer Test Al,80h ; Check if ready Jz Zl1a ; Mov Dx,OUTPUT_STATUS_PORT2 Mov Al,STROBE_HIGH ; Strobe high Out Dx,Al ; Mov Al,STROBE_LOW ; Strobe low Jmp NextInst3 ; Delay NextInst3: Out Dx,Al ; Cmp Bl,0Ah ; First or second time or last Je ByeBye ; Cmp Bl,0Dh ; Carriage return? Je ThrowLf2 ; Mov Al,0Dh ; Jmp Tg2 ; ThrowLf2: Mov Al,0Ah ; Jmp Tg2 ; ; ByeBye: Pop Dx ; Pop Bx ; Pop Ax ; Ret ; End_Of_Interrupt_Code EQU $ INTERRUPT_CODE ENDS STACKSEG Segment PARA STACK 'STACK' db 1024 dup (0) TOS EQU $ STACKSEG ENDS END Entry