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  1. #define BIT_POS(N)            ( 1U << (N) )
  2. #define SET_FLAG(N, F)        ( (N) |= (F) )
  3. #define CLR_FLAG(N, F)        ( (N) &= -(F) )
  4. #define TST_FLAG(N, F)        ( (N) & (F) )
  5. #define BIT_RANGE(N, M)       ( BIT_POS((M)+1 - (N))-1 << (N) )
  6. #define BIT_SHIFTL(B, N)      ( (unsigned)(B) << (N) )
  7. #define BIT_SHIFTR(B, N)      ( (unsigned)(B) >> (N) )
  8. #define SET_MFLAG(N, F, V)    ( CLR_FLAG(N, F), SET_FLAG(N, V) )
  9. #define CLR_MFLAG(N, F)       ( (N) &= ~(F) )
  10. #define GET_MFLAG(N, F)       ( (N) & (F) )
  11. #include <stdio.h>
  12. void main()
  13. {
  14.   unsigned char ascii_char = 'A';        /*  char = 8 bits only */
  15.   int test_nbr = 10;
  16.   printf("Starting character = %c\n", ascii_char);
  17.   /*  The 5th bit position determines if the character is
  18.       uppercase or lowercase.
  19.       5th bit = 0  - Uppercase
  20.       5th bit = 1  - Lowercase      */
  21.   printf("\nTurn 5th bit on = %c\n", SET_FLAG(ascii_char, BIT_POS(5)) );
  22.   printf("Turn 5th bit off = %c\n\n", CLR_FLAG(ascii_char, BIT_POS(5)) );
  23.   printf("Look at shifting bits\n");
  24.   printf("=====================\n");
  25.   printf("Current value = %d\n", test_nbr);
  26.   printf("Shifting one position left = %d\n",
  27.          test_nbr = BIT_SHIFTL(test_nbr, 1) );
  28.   printf("Shifting two positions right = %d\n",
  29.          BIT_SHIFTR(test_nbr, 2) );
  30. }
Runtime error #stdin #stdout 0.01s 1720KB
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stdin
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Standard input is empty
stdout
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Starting character = A

Turn 5th bit on = a
Turn 5th bit off = `

Look at shifting bits
=====================
Current value = 10
Shifting one position left = 20
Shifting two positions right = 5
https://ideone.com/YOpRN
language:
C (gcc 8.3)
created:
13 years ago
visibility:
public

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