OSDEV Community - Re: ISR&#039;s ;/

Forums

OSDEV Forums

home | post reply | threaded view | help

Boardwalk :: Forum List

Operating System Development Forums

ASM

MrKaktus
User

Junior Osdever

Posts: 12

Karma: 1

ISR's ;/ - 2005/12/20 03:13 I have remap IRQ, set PIT and then load IDT (which has all selectors set to non present). At end I turn on all Master and Slave IRQ's and NMI. (Code below).
And when I'm calling STI there ocurrs 3rd general protection fault ;/.
So I don't know what Is wrong ;/. Please help.

; (Inicjacja PIC)
; Przemapowanie IRQ na odpowiednie numery INT

; ICW 1
mov al,0x11 ; Komputer AT/PS-2 z kaskada ukladow
out 0x20,al ; |-Master i Slawe. IRQ inicjowane zboczem.
out 0xA0,al ;/ Bedzie wyslany bajt ICW4.

mov al,0x20 ; ICW 2
out 0x21,al ; |_Ustawiamy nowe numery INT dla IRQ.
mov al,0x28 ; | IRQ 0-7 maja numery 0x20-0x27 (32-39)
out 0xA1,al ;/ IRQ 8-15 maja numery 0x28-0x2F (40-47)

mov al,0x04 ; ICW 3
out 0x21,al ; |_Ustawiamy polaczenie Slave z Master.
mov al,0x02 ; | Master ma traktowac IRQ2 jako wywolanie Slave.
out 0xA1,al ;/ Slave ma wysylac IRQ2 do Mastera.

mov al,0x01 ; ICW 4
out 0x21,al ; |-Tryb pracy zgodny z 8086/88,
out 0xA1,al ;/ wysylamy 8bitowy numer INT.

; (Inicjacja PIT)
; Ustawienie generatora 8253/8254 na generowanie
; przerwania IRQ0 z czestotliwoscia 100Hz (99.998Hz)

mov al, 0x34 ;_Wysylamy rozkaz zaprogramowania
out 0x43, al ;/ generatora 0, na tryb 2. (00110100b)
mov al, 156 ;_Wysyla LSB (156)
out 0x40, al ;/
mov al, 46 ;_Wysyla MSB (46)
out 0x40, al ;/ [ (46*256)+156=11932 - dzielnik zegara]

; (Inicjacja IDT)
; Zaladowanie do rejestru LIDT adresu tablicy IDT
; i odblokowanie wszystkich linii IRQ oraz NMI.

lidt [IDT_Reg] ; Zaladowanie tablicy IDT

xor al, al ;Odblokowujemy wszystkie IRQ
out 0x21, al ;/dla ukladu 8259A Master
xor al, al ;Odblokowujemy wszystkie IRQ
out 0xA1, al ;/dla ukladu 8259A Slave

in al, 0x70 ;
and al, 0x7F ; |-Wlaczamy przerwanie NMI
out 0x70, al ;/

sti ; Wlaczamy obsluge przerwan

jmp $

.
.
.

IDT_Tab:

; Na poczatku IDT jest pelne pustych wpisow

%rep 0x40 ; 0x38
dw 0x0000 ; Offset 0-15
dw 0x08 ; Selektor segmentu kodu DPL 0
db 00000000b ; Wyzerowane, Reserved
db 00001110b ; NIE-OBECNY , DPL0, 32bit
dw 0x0000 ; Offset 16-31
%endrep

IDT_End:

IDT_Reg: dw IDT_End - IDT_Tab - 1
dd IDT_Tab

End of code.

| | The administrator has disabled public write access.

OSDEV Community	Advertisement

gaf
User

Platinum Osdever

Posts: 153

Karma: 10

Re: ISR's ;/ - 2005/12/20 10:13 Could it be that you simply forgot to paste the ISR's address into the IDT entries ?

Code:
%rep 0x40 ; 0x38 dw 0x0000 ; Offset 0-15 [b]
	\| \| The administrator has disabled public write access.

MrKaktus
User

Junior Osdever

Posts: 12

Karma: 1

Re: ISR's ;/ - 2005/12/20 15:21 No , I make it specially (present bit is set to ZERO - 0). I have solve it by setting all IDT entries to one ISR handler which is doing nothing. Now I will separate it One by One and write ISrs for each of them.

| | The administrator has disabled public write access.

gaf
User

Platinum Osdever

Posts: 153

Karma: 10

Re: ISR's ;/ - 2005/12/21 11:48 As Jaaman has already said in your other thread at osdev.org, setting the present bit to zero won't solve the problem as a triple fault is raised whenever an interrupt can't be dispatched due to an invalid/non-active IDT entry. If you use the code snipped that follows to create a basic IDT that delivers all IRQs to a single handler you shouldn't get GPFs any longer:

Code:

mov edi, IDT_TAB

mov ecx, 0x30 ; How many entries ? 



idt_exception_entry:

mov eax, exception

stosw

mov eax, 0x8E000008

stosd

mov eax, exception

shr eax, 16

stosw

loop idt_exception_entry



...



exception:

mov ax, 0x10

mov ds, ax

mov es, ax

mov fs, ax

mov gs, ax

mov ss, ax



mov esp, 0x7e00



call print_something

hlt

regards,
gaf

| | The administrator has disabled public write access.

MrKaktus
User

Junior Osdever

Posts: 12

Karma: 1

Re: ISR's ;/ - 2005/12/29 07:10 Ok, i have solved it on my own way. look thread at osdev.org

| | The administrator has disabled public write access.

Boardwalk :: Forum List Operating System Development Forums ASM

MamboBoard Forum Component 1.2.2
MamboBoard Components

A WebArticles site. Sponsored by Evoleto. Motorola V525 / Business Directory / Delaware Incorporation / Home Made Bazaar