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Re: [Nasm-users] Handling timer interrupt
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From: zak100 <zul...@ya...> - 2009-08-07 05:23:18
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Hi, I want to print the time how long the kernel is in action at each timer interrupt instance using mesgA. I am working on the information you have provided and reply you soon. I want to handle interrupt 1C. I would check this code again. Zulfi. zak100 wrote: > > Hi, > I am trying to handle timer interrupt in a OS like code. I have got a > bootloader whose code is given below and is working (I am able to see the > mesg at the start up): > %define bootseg 0 > %define bootoff 7C00h > > %define loadoff 7E00h > > > > > ORG 7c00h ;Because BIOS loades the OS at > ; address 0:7C00h so ORG 7C00h > ; makes that the refrence to date > ; are with the right offset (7c00h). > > > > ; CS = 0 / IP = 7C00h // SS = ? / SP = ? > ; You are now at address 7c00. > jmp start ;Here we start the, BIOS gave us now the control. > > > > ;/////////////////////////////////////////// > ;//Here goes all the data of the program. > ;/////////////////////////////////////////// > > xCursor db 0 > yCursor db 0 > > > nSector db 0 > nTrack db 0 > nSide db 0 > nDrive db 0 > > nTrays db 0 > > ; > szReady db 'Are You Ready to start Loading the OS...',0 > szErrorReadingDrive db 'Error Reading Drive, Press any Key to > reboot...',0 > ;//Done Reading a track. > szPlaceMarker db '~~~~',0 > szDone db 'Done',0 > > pOS dw loadoff > ;//Points to where to download the Operating System. > > ;///////////////////////////////// > ;//Here the program starts. > ;///////////////////////////////// > > > start: > > CLI ;Clear Interupt Flag so while setting > ;up the stack any interrupt would not be fired. > ;----------------STACK > mov AX,7B0h ;lets have the stack start at 7c00h-256 = 7B00h > mov SS,ax ;SS:SP = 7B0h:256 = 7B00h:256 > mov SP,256 ;Lets make the stack 256 bytes. > > XOR AX,AX ;Makes AX=0. > MOV ES,AX ;Make ES=0 > mov DS,ax > > > STI ;Set Back the Interupt Flag after > ;we finished setting a stack frame. > > Call ClearScreen ;ClearScreen() > LEA AX,[szReady] ;Get Address of szReady. > CALL PrintMessage ;Call PrintfMessage() > CALL GetKey ;Call GetKey() > > mov bp, 1 ; sectors to load > CALL DownloadOS > ; CALL GetKey ;Call GetKey() > CALL GiveControlToOS ;Give Control To OS. > > ;///////////////////////////////////// > ;//Prints a message to the screen. > ;///////////////////////////////////// > PrintMessage: > > mov DI,AX ;AX holds the address of the string to Display. > Mov byte [xCursor],1 ;Column. > > ContinuPrinting: > > cmp byte [DI],0 ;Did we get to the End of String. > JE EndPrintingMessage ;if you get to the end of the string > return. > > mov AH,2 ;Move Cursor > mov DH,[yCursor] ;row. > mov DL,[xCursor] ;column. > mov BH,0 ;page number. > INT 10h > INC byte [xCursor] > > mov AH,0Ah ;Display Character Function. > mov AL,[DI] ;character to display. > mov BH,0 ;page number. > mov CX,1 ;number of times to write character > INT 10h > > INC DI ;Go to next character. > > JMP ContinuPrinting ;go to Print Next Character. > > EndPrintingMessage: > > Inc byte [yCursor] ;So Next time the message would > ;be printed in the second line. > > cmp byte [yCursor],25 > JNE dontMoveCorsurToBegin > Mov byte [yCursor],0 > > dontMoveCorsurToBegin: > ret > > > ;PrintMessage EndP > ;////////////////////////////////////// > ;//Waits for the user to press a key. > ;////////////////////////////////////// > GetKey: ; PROC > > mov ah,0 > int 16h ;Wait for a key press. > Ret > > ;/////////////////////////////////////////// > ;//Gives Control To Second Part Loader. > ;/////////////////////////////////////////// > GiveControlToOS: > > LEA AX,[szDone] > Call PrintMessage > CALL GetKey > > jmp 7E0h:40h > > mov ax, [loadoff + 18h] > > push 7E0h > push ax > retf > > ;/////////////////////////////////// > ;//Clear Screen. > ;/////////////////////////////////// > ClearScreen: > > mov ax,0600h ;//Scroll All Screen UP to Clear Screen. > mov bh,07 > mov cx,0 > mov dx,184fh > int 10h > > Mov byte [xCursor],0 ;//Set Cursor Position So next > ;//write would start in > ;//the beginning of screen. > Mov byte [yCursor],0 > > Ret > > ;///////////////////////////////// > ;//PrintPlaceMarker. > ;///////////////////////////////// > PrintPlaceMarker: > > LEA AX,[szPlaceMarker] > CALL PrintMessage ;Call PrintfMessage() > ; CALL GetKey ;Call GetKey() > ret > > ;/////////////////////////////////// > ;//DownloadOS > ;/////////////////////////////////// > DownloadOS: > > mov byte [nDrive],0 > mov byte [nSide],0 > mov byte [nTrack],0 > mov byte [nSector],1 ; desired sector - 1! > > ContinueDownload: > > INC byte [nSector] ;Read Next Sector. > cmp byte [nSector],19 ;Did we get to end of track. > JNE StayInTrack > > CALL PrintPlaceMarker ;Print now '~~~~' so the user would > ;know that we finished reading a track > INC byte [nTrack] ;If we get to end of track Move to > next track. > mov byte [nSector],1 ;And Read Next Sector. > CMP byte [nTrack],5 ;Read 5 Tracks (Modify this value > ;to how much Tracks you want to read). > JE EndDownloadingOS > > StayInTrack: > > ;ReadSector(); > Call ReadSector > dec bp > jz EndDownloadingOS > > > JMP ContinueDownload > ;If didn't yet finish Loading OS. > > EndDownloadingOS: > > ret > > ;//////////////////////////////////////// > ;//Read Sector. > ;//////////////////////////////////////// > ReadSector: > > mov byte [nTrays],0 > > TryAgain: > > mov AH,2 ;//Read Function. > mov AL,1 ;//1 Sector. > mov CH,[nTrack] > mov CL,[nSector] ;//Remember: Sectors start with 1, not 0. > mov DH,[nSide] > mov DL,[nDrive] > Mov BX,[pOS] ;//ES:BX points to the address > ;to were to store the sector. > INT 13h > > jnc EndReadSector > > mov AH,0 ;Else Reset Drive . And Try Again... > INT 13h > cmp byte [nTrays],3 ;Check if you tryed reading > ;more then 3 times. > > JE DisplayError ; if tryed 3 Times Display Error. > > INC byte [nTrays] > > jmp TryAgain ;Try Reading again. > > DisplayError: > LEA AX,[szErrorReadingDrive] > Call PrintMessage > Call GetKey > mov AH,0 ;Reboot Computer. > INT 19h > > > EndReadSector: > ADD WORD [pOS],512 ;//Move the pointer > ;(ES:BX = ES:pOS = 0:pOS) 512 bytes. > ;//Here you set the varible > ;pOS (pOS points to were BIOS > ;//Would load the Next Sector). > Ret > > ;//////////////////////////////////// > ;// > ;//////////////////////////////////// > > times 510 - ($ - $$) db 0 > db 55h, 0AAh > ;------------------- > > > > An then I have a kernel code which includes a file also: > > %include "lib.inc" > mov ax, 7E0H > mov ds,ax > mov es,ax > mov si, msg > > mov ah, 0Eh > mov bx, 7 > top: > lodsb > cmp al, 0 > jz blackhole1 > int 10h > jmp short top > > blackhole1:install 6 > > blackhole: > hlt > jmp blackhole > > msg db 'Welcome to the Kernel!', 0 > msgA db 'Total minutes elapsed since Kernel start is', 0AH, 0DH > clkcounter db 0 > secs db 0 > mins db 0 > > times 0x200-($-$$) db 0 > > > The include file is given below: > > %macro install 1 > push ax > mov al,%1 > mov ah, 0eh > int 10h > pop ax > ;push ds > ;mov ax, 0 > ;mov word[%1*4],isr_add > ;mov word[%1*4+2],cs > ;pop ds > %endmacro > > isr_add: > cli > inc byte [byte cs:clkcounter] > cmp byte [byte cs:clkcounter],18 > jz handle_secs > sti > iret > handle_secs: > mov byte [byte cs:clkcounter],0 > inc byte [byte cs:secs] > cmp byte [byte cs:secs],60 > jz handle_mins > sti > iret > handle_mins: > mov byte [byte cs:secs],0 > inc byte [byte cs:mins] > push ds > push es > > xor ax,ax > mov ds,ax > mov es,ax > ; should probably set up a sane stack here, too. > mov si,msgA ; "our dear string" > > ;mov bx,7 > mov ah,0Eh > msgloop: > lodsb > or al,al > jz end44 > int 10h ; since we're still in RM, we can use bios. > jmp msgloop > end44: pop es > pop ds > sti > iret > sti > iret > > For compilation I am using following commands: > nasm -f bin bootmz.asm -o boot.bin > > nasm -f obj test_k.asm > > > > alink -oEXE test_k.obj > > > copy /b boot.bin+test_k.exe image.bin > partcopy image.bin 0 323 -f0 > > Can somebody plz help me with this? > > Zulfi. > -- View this message in context: http://www.nabble.com/Handling-timer-interrupt-tp24847167p24859029.html Sent from the nasm-users mailing list archive at Nabble.com. |
