bits.c File Reference

Function Documentation

byte getbit	(	byte	b,
		int	n
	)

Definition at line 9 of file bits.c.

References byte.

Referenced by decode_bch().

00014 {
00015   return (b >> (8-n)) & 1;
00016 }

unsigned int getbitint	(	unsigned int	b,
		int	n
	)

Definition at line 18 of file bits.c.

Referenced by checkcrc4(), encode_bch(), make_backward_control(), make_forward_control(), and makecrc4().

00023 {
00024   return (b >> (16-n)) & 1;
00025 }

void printbyte

(

byte

)

Definition at line 59 of file bits.c.

00061 {
00062   int j;
00063   for(j=7;j>=0;j--)
00064     if ((int) b  & (1 << j))
00065       printf("1");
00066     else
00067       printf("0");
00068   printf("\n");
00069 }

void printint

(

unsigned int

)

Definition at line 71 of file bits.c.

00073 {
00074   int j;
00075   for(j=15;j>=0;j--)
00076     if ((int) b  & (1 << j))
00077       printf("1");
00078     else
00079       printf("0");
00080   printf("\n");
00081 }

int random_bit

(

void

)

Definition at line 84 of file bits.c.

Referenced by randomize_byte().

00086           : either a 1 or a 0.  
00087  *
00088  * there is approximately an equal chance of each.
00089  */
00090 {
00091   static int random_counter = -1;
00092   static int r;
00093  
00094   if (random_counter == -1) {
00095     r = rand();
00096     random_counter = 30;
00097   }
00098   return ((r & (1 << random_counter--))?1:0);
00099 }

void randomize_byte

(

byte *

)

Definition at line 101 of file bits.c.

References random_bit(), and setbit().

Referenced by code_audio().

00105 {
00106   int i;
00107 
00108   for (i=1;i<=8;i++)
00109     setbit(b,i,random_bit());
00110 }

void setbit	(	byte *	b,
		int	n,
		byte	v
	)

Definition at line 28 of file bits.c.

Referenced by encode_bch(), and randomize_byte().

00032        : pointer to the byte.  output: none.  side effect: changes
00033   the particular bit in the byte
00034 */
00035 {
00036   if (v != 0)
00037     *b = (*b | (128 >> (n-1))); /*turn the bit on*/
00038   else
00039     *b = (*b & (~(128 >> (n-1)))); /*turn the bit off*/
00040 }

void setbitint	(	unsigned int *	b,
		int	n,
		byte	v
	)

Definition at line 43 of file bits.c.

Referenced by make_backward_control(), and make_forward_control().

00049        : pointer to the unsigned int.  output: none.  side effect: 
00050         changes the particular bit in the byte
00051 */
00052 {
00053   if (v != 0)
00054     *b = (*b | (32768 >> (n-1))); /*turn the bit on*/
00055   else
00056     *b = (*b & (~(32768 >> (n-1)))); /*turn the bit off*/
00057 }

Generated on Sun Jul 16 16:27:45 2006 by

1.3.9.1


Functions
byte	getbit (byte b, int n)
unsigned int	getbitint (unsigned int b, int n)
void	setbit (byte *b, int n, byte v)
void	setbitint (unsigned int *b, int n, byte v)
void	printbyte (byte b)
void	printint (unsigned int b)
int	random_bit (void)
void	randomize_byte (byte *b)

bits.c File Reference

Functions

Function Documentation