C Programming Code Examples
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Program to write data in DMA Mode
/* Program to write data in DMA Mode */
# include<iostream.h>
# include<stdio.h>
# include<conio.h>
# include<stdlib.h>
# include<dos.h>
void main()
{
clrscr();
union REGS regs;
int ans;
char arr[1000];
outp(0x3f2,0x1c); //Motor On
delay(200);
outp(0x3f5,0x0f); //Command Code
delay(200);
outp(0x3f5,0x00); //Command Code
delay(200);
outp(0x3f5,0); //Cylinder no.
delay(200);
outp(0x3f5,0x08); //Sense Interrupt Command
delay(200);
ans=inp(0x3f5); //Reading ST0 in data register
delay(100);
ans=inp(0x3f5); //pcn
cout<<endl<<hex<<ans;
delay(200);
outportb(0x12,0); /*initialization of DMA Mode*/
delay(200);
outportb(0x11,10); /*supplying Mode Byte*/
int ar=FP_OFF(arr);
int ar1=FP_SEG(arr);
outportb(0x10,2); /*supplying channel no. on port 10*/
regs.h.ch = (ar1)&(0x0f00);
regs.x.ax = regs.h.ah+ar;
(regs.h.ch)++;
outportb(0x04,regs.h.al);
delay(200);
outportb(0x04,regs.h.ah);
delay(200);
outportb(0x81,regs.h.ch);
delay(200);
outportb(0x05,1);
// DMA End
//READ command
delay(200);
outportb(0x3f5,46); //Command Code
delay(200);
outportb(0x3f5,0); //Command Code
delay(200);
outportb(0x3f5,0); //Cylinder no.
delay(200);
outportb(0x3f5,0); //Head Addr
delay(200);
outportb(0x3f5,3); //Record
delay(200);
outportb(0x3f5,2); //Sector size
delay(200);
outportb(0x3f5,5); //EOT
delay(200);
outportb(0x3f5,21); //GPL
delay(200);
outportb(0x3f5,10); //DTL
//result
delay(200);
// st0
int st0 = inportb(0x3f5);
printf("
st0 = %x",st0);
if(inportb(0x3f5) & (192)!=0)
{
printf("
st0= %d",st0);
cout<<"
Abnormal termination st0";
delay(200);
outp(0x3f2,0x0c); //Motor off
exit(0);
}
delay(200);
int st1 = inportb(0x3f5);
printf("
st1 = %x",st1);
if((st1=inportb(0x3f5)) !=0)
{
printf("
st1=%d ",st1);
cout<<"
Abnormal termination st1";
delay(200);
outp(0x3f2,0x0c); //Motor off
exit(0);
}
delay(200);
int st2 = inportb(0x3f5);
printf("
st2 = %x",st2);
if((st2=inportb(0x3f5)) != 0)
{
cout<<"st2= "<<st2;
cout<<"
Abnormal termination st2";
delay(200);
outp(0x3f2,0x0c); //Motor off
exit(0);
}
cout<<"
Successful Termination";
delay(200);
cout<<"
c= "<<inportb(0x3f5);
delay(200);
cout<<"
h= "<<inportb(0x3f5);
delay(200);
cout<<"
r= "<<inportb(0x3f5);
delay(200);
cout<<"
n= "<<inportb(0x3f5);
delay(200);
outp(0x3f2,0x0c); //Motor off
getch();
}
In C, the "main" function is treated the same as every function, it has a return type (and in some cases accepts inputs via parameters). The only difference is that the main function is "called" by the operating system when the user runs the program. Thus the main function is always the first code executed when a program starts. main() function is a user defined, body of the function is defined by the programmer or we can say main() is programmer/user implemented function, whose prototype is predefined in the compiler. Hence we can say that main() in c programming is user defined as well as predefined because it's prototype is predefined. main() is a system (compiler) declared function whose defined by the user, which is invoked automatically by the operating system when program is being executed.
Function clrscr() clears the screen and moves the cursor to the upper left-hand corner of the screen. If you are using the GCC compiler, use system function to execute the clear/cls command. clrscr() function is also a non-standard function defined in "conio.h" header. This function is used to clear the console screen. It is often used at the beginning of the program (mostly after variable declaration but not necessarily) so that the console is clear for our output.
Writes the C string pointed by format to the standard output (stdout). If format includes format specifiers (subsequences beginning with %), the additional arguments following format are formatted and inserted in the resulting string replacing their respective specifiers. printf format string refers to a control parameter used by a class of functions in the input/output libraries of C programming language. The string is written in a simple template language: characters are usually copied literally into the function's output, but format specifiers, which start with a % character, indicate the location and method to translate a piece of data (such as a number) to characters. "printf" is the name of one of the main C output functions, and stands for "print formatted". printf format strings are complementary to scanf format strings, which provide formatted input (parsing). In both cases these provide simple functionality and fixed format compared to more sophisticated and flexible template engines or parsers,
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