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C In DOS :: Interrupts ,Interrupt Vector Table IVT, Interrupt Service Routines ISR
Lot of people are contacting me for more information on interrupts, IVTs and ISRs. I request you to share any information and queries you have on this forum.
Pointers and its types :
- A near pointer is 16 bit long . It uses the current contents in CS register of CPU. Near pointer is limited to 64KB of memory
- A Far pointer is 32 bit long and can access more than 64KB , Huge pointers are also 32 bit long but they use normalization procedure .
Addresses are usually stored in Segment:offset pair and u can use the macro MK_FP to create far
pointers using Segment and offset addresses . Say segment is 0xB000 and offset is 8000 then
MK_FP(0xB000,8000) would give u a far pointer.
The CPU Registers :
Microprocessors usually have internal storage locations to hold intermediate output called 'registers' . There are in all fourteen CPU registers in 80x86 family of processors as given by
(a) Scratch Pad registers : These are data registers , Four in number as given by
- AX : Accumulator , Pseudo variable _AX
- BX : Base ,pseudo variable _BX
- CX : Count ,pseudo variable _CX
- DX : Data , pseudo variable _DX
These are 16 bit registers that can be accessed either as 16 bit or 8 bit entities.
(b) Segment registers : The 8086 family of processors refers to any memory location as Segment (16 Bit ):offset (16 Bit ) pair . Specific segments are accessed using Segment registers . These are under ,
- The CS register identifies the code segment , which contains the program currently under execution.
- Data segment and Extra segment are identified by DS and ES registers
- The Stack segment is identified by SS segment.
(c) Offset Registes :
- Instruction Pointer IP
- Stack Pointer SP
- Base pointer BP
- Source Index SI
- Destination Index DI
(d) Flags Registers :
There are 9 one bit registers and 7 bits are unused.
Interrupts and Interrupt Vector Table
Interrupt occurs as a signal for the microprocessor to stop whatever it is doing currently . It tells the microprocessor that something important has happend and its attention is needed . The signal is usually generated by the hardware , i.e., Say when a key is hit the keyboard interrupt is generated . C provides a library function for generating interrupts called int86().Every interrupt (either software or hardware ) has a number associated with it . For example the number Ketboard interrupt is 9.
When an interrupt is generated , the processor stops its current activity and activates a memory resident routine called Interrupt Service Routine ISR , The addresses of ISRs are stored in low memory area called the Interrupt Vector Table or the IVT.
A sample call to int86() function is given below ,
int86(8,&i,&o)
where i and o are unions of type REGS which is defined as follows
union REGS {
struct WORDREGS x;
struct BYTEREGS h;
};
struct BYTEREGS {
unsigned char al, ah, bl, bh;
unsigned char cl, ch, dl, dh;
};
struct WORDREGS {
unsigned int ax, bx, cx, dx;
unsigned int si, di, cflag, flags;
};
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Created on 19
1. VGA
how can i acess the VGA memory or what is the address of the VGA memory?
sachin c. moh"ite on 22
2. please tell me about VDU
hello,
i have a problem ,i have complete my steganography tool in c but my teacher said to me
"please divide the screen in two sub parts and show both the pictures in different window
" so please tell me the code for this problem
ashish sharma on 10
3. 1.IVT
sir i know each interrupt has its own interrupt number but i dont know that
interrupt number's, please send to me intrrupt numbers for all (0-256)interrupts and from which
variable i will get what valueplease mention that if possible.Like int86(18,& inregs,& out
regs) will retun memory size in "outregs.x.ax" in this way the content of other variable
in the unoion after calling int86().
Shankha Acharya on 5
4. hardware interrupt
Hello sir, i want to know about hardware interrupt in c,and code for hardware interrupt.
Lohar Vinod on 28
5. May i interrupt?
Where is the closest intersection? Im hungry..
Manny Poohkiaw on 19
6. Reach to high
Sucess happens by practice and putting every thing into action.
Start doing definetely you will finish
satyaprasad rangaraju on 15
7. for interupt requirment for the project
i want all the intruupt for my project due to i need to the intruupt
amit arora on 7
8. interrupt victor
I would like to jnow more about interrupt victors
faizbazanboor on 26
9. Getting Password
How to get Bios password in c program? code plz??
Sandeep A. Koli on 8
10. c programming
Is it possible to play a .wav file in C/C++ only.
If possible then how to do it with interrupts...
And also please tell the best way to study interrupt programming in C.
Sandeep A. Koli on 8
11. interrupt
sir i know each interrupt has its own interrupt number but i dont know that interrupt
number's, please send to me intrrupt numbers for all (0-256)interrupts. Thank you
by
R.Jawa
by
Jawa prabhu on 2
12. to know about advance topics in Keyboard and Mouse Intrupt Handlers
Sir! I want to know about advance topics in Keyboard and Mouse Intrupt Handlers.
Thank U
P. MARIMUTHU on 30
13. Interrupt vector
sir, i want to know the interrupt vectors available in c. please send me the interrupts available.
R. Jyothi Priya on 10
14. interrupt number of pc speaker
please can any one tell me that how can we generate sound through speaker without using sound card please send me a code example
deepak on 27
15. cd-rom Interrupt
Hello sir I want to Interrupt number of cd-rom plese kindly send to mail.
rajesh on 18
16. interrupt service codes
want to know about the interrupts of int86 and how they works.
abraham johnson on 7
17. Key board interrrut...
how to block and release the keyboard( keys.)?
samuthiram on 5
18. handling of operating system through DOS
how to control the whole computer system with DOS
manish kumar srivastava on 30
19. Sound card access in DOS
How to access sound card,i.e.,making sound through external speaker ,not by internal speaker,in borland c version 3.00.
manoj singh on 7
20. Interrupt vector table
i want to know the details of interrupt vector table and the service nos.how can i access the ivt
in a system
joejith on 2
21. sir i want the intrrupt code for making virus in c which is coomon code in all virus
sir my sir has asked the answer of this question that what is the common code in all viruses .
they have given me one hint that the code is inturrupt pointer find this code.
pls send this code to me.
thanx
ashwini kumar on 28
22. architecture
the int86() function doesnt seem to work on windows might be due to different architecture
......what should i do??are there different isr addresses for working in
windows now?????
because whatever m using doent seem to work...why is that so........m currently following
yashavant kanetkar..
vikram datt rana on 22
23. How can delete directory using intdos()
Dear sir,
How can delete directory using intdos() function .Please send it's code.Thanks
jaipratap singh dhakad on 20
24. CPU information
Can you help me to identify my CPU details(vendor name,other details)through DOS based programming in C.I use a 16 bit turbo c/C++ compiler.
sudhanshu kotlia on 7
25. Keybord Interrupt
Keybord Interrupt
I want to know how int86() can be used to create an keyboard interrupt. I want a full code for
that in C.
Narndra Verma on 6
26. interrupt vector
i want a list of all interrupt service number which we can use in C or C++.
Ganesh Pratap Singh Kushwaha on 25
27. How to get Bios password in c program? code plz??
w to get Bios password in c program? code plz??
vaishali patil on 4
28. How to get Bios password in c program? code plz??
Hello...
I want to display bios password through c language?
How to do it? If any code plz send it to me?
It's helpful to understand the system programing for bios..
Thanks in advance
Amit Prakash Pawar on 4
29. How to get Bios password in c program? code plz??
Hello...
I want to display bios password through c language?
How to do it? If any code plz send it to me?
It's helpful to understand the system programing for bios..
Thanks in advance
Amit Prakash Pawar on 4
30. Writing Device Drivers for nVIDIA Geforce 4200 Ti series Graphics Card
I would like to know about nVIDIA chipset and internals
Chintan Desai on 25
31. Soun card handling
how can i play wave and midi files using C programing and we want the output through sound card?
Ankur Sachan on 12
32. keyboard interfacing program using c51
iam doing a project wherein i need t o develop keyboard interface.
harish on 23
33. Hardware Interrupt
Please tell all the interrupts and about int86 and int86x. give me the list of hardware interrupts using in c programme
Ganesh on 15
34. intrrupt
i need usefull tips about c intrrupt & graphics
m.ramkumar on 11
35. Computer
BIOS Intrupt Table pdf Needed
Mohammad Bashiri on 14
36. sound card access in c language
sir, i am working on a project which require mp3 player with serial port controller , I know how to program serial port but how to write mp3 player by C
Manoj Jaiswal on 10
37. sound card access in c language
sir, i amworink on a project which require mp3 player with serial port controller , I know how to program serial port but how to write mp3 player by C
Manoj Jaiswal on 10
38. intrupt programming
sir,
I want to wirte hardware program in c language. how to write please details give me.
thanks
vimal on 27
39. I want some programs of C++ for reading disk info, for reseting the BIOS.
I want some programs of C++ for reading disk info, for reseting the BIOS.
Jaiprakash d solanki on 2
40. Hardware intrrupt
HOw can create hardware intrrupt using c coding
Deepak Singh on 12
41. think about c ?
hello my dear , i want the list of ivt table list with different types of its function
rajesh on 7
42. int86 interrupts & information about it.
i want to know about the interrupts in int86 for handling files
pramila khot on 2
43. opertaing system designing
how to start to designed the operating system in c language?and what is the first module?
vishal prajapati on 16
44. IVT
Please write me about the IVT(interrupt Vector Table)
anton tamang on 13
45. music
how music is played in c
raj yadav on 10
46. .wav in c
how wav files are implemented in turbo c
RAJU PRASAD on 10
47. interrupts
tell me about all the interrupts and about int86 and int86x
RAJU PRASAD on 10
48. .wav in C
Is it possible to play a .wav file in C/C++ only.
If possible then how to do it with interrupts...
And also please tell the best way to study interrupt programming in C.
Ayush Sharma on 7
49. IVT
i want to know about Interrupt Vector Table. As i am working in TSR screen saver.
Romasa on 18
50. interrupt vectors
name the interrupt vectors of 8086?
prashant saroha on 27
51. interrupt vector table
Sir I want to know abut interrupt,Types of interrupt and Interrupt Vector Table?
HARSIMRAN KAUR on 17
52. int86 function to deal with monitor resolution
int86 function to deal with monitor resolution without calling inbuilt function so to make the program faster
hariprasad k on 12
53. C interrupt
tell me about C interrupt in detail
Manikanth Kumar on 11
54. int86 function to initialise CD ROM in C
I want to know the codes to initialise CD ROM in C
santosh v gogoi on 11
55. Software Engg.
i want to know about different interrupt available for
file management in C or using int86(),,
how to create,modified,delete,change type etc..
Alpesh Donga on 3
56. playing music in c
how 2 play music in c
prasanth varghese on 7
57. details of interrupt vector table and the service routines
i want to know the details of interrupt vector table and the service nos. spacially i want to access the sound card through c programming. can you help me?
Mrinal Sen on 20
58. Interrupts
How to Interrupt the System using C-program
&
How to use signal.h combining the interrupt concept yields to SECURITY SOFTWARE
Neo Andreson.K on 14
59. how ro read and image (JPG) and process it
how can we read image and process it, can we devide pixel in subpixel. I have thorlab camra, and flypgr cam
kiran sapkl on 9
60. datail about IVT and ISR
Can i change the address of the ISR in the IVT for some particular interrupt? if so, how?
i want to know,how i can replace already existing isr with new one using int86 function so
that change should be permanent even if computer starts again. i want simple & full coding in c
sayyed abdul majid on 19
61. keyboard interrupt
sir,
i want to know,how i can replace already existing isr with new one using int86 function so
that change should be permanent even if computer starts again.
i want simple & full coding in c(by taking eg. of keyboard).
(in other words, i want to prepare a virus)
dharmender on 27
62. using mouse in graphics mode
Sir,i want know about how to initialize mouse in graphics mode and how it works.i also want codes for this.
Yamini Priya on 23
63. Serial Interface
How can i write an ISR for serial interface ie for serial port??
Bhagavath on 29
64. interrupt
how can i interrupt the system externally using c program?
kanagaraj on 3
65. int86
I gone through many c books but i found only small material on int86 or on int86x How could we interpt with diffrent hardware using c functions.
manoj jaiswal on 25
66. hardware interrupt program
Dear sir,can you tell me what I must notice when programming used by hardware interrupt?Thanks.
breezee on 24
67. Keystroke Identify
How can i find the key stroke from the keyboard while working other programs . Pls send a complete/any related code to count the number of key strokes while working in any application
yesu on 23
68. how to make a game like prince in c
can we make a game like prince without pthread.h
please provide me with the code and is there any easy way to test hittest property
sreelal.s.l on 15
69. TSR
want to know about TSR and ISR
Bhuban Tandukar on 22
70. Modifying the IVT
Can i change the address of the ISR in the IVT for some particular interrupt? if so, how?
Chetan H Nadiger on 19
71. Keybord Interrupt
I want to know how int86() can be used to create an keyboard interrupt. I want a full code for that in C.
Ajeet Kumar Gupta on 30
72. Interacting with Sound Card
Hi, could u plz give me some tips on how to send data to the sound port and make the speakers to play that sound data. Is there any interrupt to send data to sound card?
Sekar on 23
73. Mr
How to program keyboard in c using interrupts. I want to:
1. execute "function A" while "up arrow" key is pressed.
2.continue execution of "function A" and execute "function B" at the same
time while "right arrow key" is pressed and still pressing "up" key.
3. continue execution of "function A" after releasing "right arrow" while
still pressing "up arrow".
Nadeem Hamed on 17
74. TSR
sir I want to know about TSR
pranav waila on 17
75. programmer insisted
hi
ramzan khan on 3
76. dos interrupts in c
sir, i want to know the interrupts of dos that are available in c. please send me the interrupts available.
Karthik.P on 24
77. System Programming in C
I want to use DOS interrupts.Please send materials for them.
Ranjith Kumar on 22
78. int86
I want to know about the interrupts of int86 and how they works
vijai on 15
79. Int86
I want to know about the interrupts of int86 and how they works.
Tarunarko Sarkar on 3
80. assking material
dear sir
at the time being i am taking the corse known as computer engenering .I want the material
about dos interrupt brife not if you can ples send me
thank you for yor copration
afework bezie on 13
81. Sound card access in DOS
How to access sound card,i.e.,making sound through external speaker ,not by internal speaker,in borland c version 3.00.
Subhrajyoti Ghosh on 19
82. mouse interrupt
How can i catch mouse interrupt
in run time by just clicking the Mouse to know the
row, col etc. ?
Manoj Pandey on 3
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