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Binary number

How can a Binary number be used in a program?

  • There are only 10 ways of using a binary number -:)

  • Define "program".
    Define "use".

    C code ? Use hex or octal instead. C does not support binary constants.

    Assembly code ? Read the manual concerning "expressions". That will explain what format is used for binary datatypes.

  • If you are asking about using binary constants, here are some public domain binary constant macros Tom Torfs published on Usenet. I'm a little concerned because last time I posted this here, the preview was correct, but the forum rendering was not -- here goes:

    ================================================================
    
    From: tomtorfs@village.uunet.be (Tom Torfs)
    Newsgroups: comp.lang.c,comp.arch.embedded
    Subject: Binary constant macros
    Date: 26 Feb 2004 07:36:35 -0800
    
    Hello All,
    
    I've been missing the lack of support for binary numeric literals in
    C. To get around it I wrote the following handy macros, which allows
    you to simply write something like:
    
    whatever = B8(10101010);
    
    and will translate as:
    
    whatever = 85;
    
    (compile-time constant)
    
    Code below... hopefully it's useful to some of you as well.
    
    greetings,
    Tom
    
    /* Binary constant generator macro
       By Tom Torfs - donated to the public domain
    */
    
    /* All macro's evaluate to compile-time constants */
    
    /* *** helper macros *** /
    
    /* turn a numeric literal into a hex constant
       (avoids problems with leading zeroes)
       8-bit constants max value 0x11111111, always fits in unsigned long
    */
    #define HEX__(n) 0x##n##LU
    
    /* 8-bit conversion function */
    #define B8__(x) ((x&0x0000000FLU)?1:0)  \ 
                   +((x&0x000000F0LU)?2:0)  \ 
                   +((x&0x00000F00LU)?4:0)  \ 
                   +((x&0x0000F000LU)?8:0)  \ 
                   +((x&0x000F0000LU)?16:0) \ 
                   +((x&0x00F00000LU)?32:0) \ 
                   +((x&0x0F000000LU)?64:0) \ 
                   +((x&0xF0000000LU)?128:0)
    
    /* *** user macros *** /
    
    /* for upto 8-bit binary constants */
    #define B8(d) ((unsigned char)B8__(HEX__(d)))
    
    /* for upto 16-bit binary constants, MSB first */
    #define B16(dmsb,dlsb) (((unsigned short)B8(dmsb)<<8)   \ 
                            + B8(dlsb))
    
    /* for upto 32-bit binary constants, MSB first */
    #define B32(dmsb,db2,db3,dlsb) (((unsigned long)B8(dmsb)<<24)    \ 
                                      + ((unsigned long)B8(db2)<<16) \ 
                                      + ((unsigned long)B8(db3)<<8)  \ 
                                      + B8(dlsb))
    
    /* Sample usage:
          B8(01010101) = 85
          B16(10101010,01010101) = 43605
          B32(10000000,11111111,10101010,01010101) = 2164238933
    */
    
    greetings,
    Tom
    

  • If this is true...

    whatever = B8(10101010);
    
    and will translate as:
    
    whatever = 85;
    

    I'm not sure I want to use this code.

    10101010 in Binary = 0xAA in Hexadecimal.

    Jon

  • Looks like Mr. Torfs has a typo. Further down just above the second of his two(!) signatures in "Sample usage:", he's got the same "... = 85" but this time it's B8(01010101), which is correct.

  • he's got the same "... = 85" but this time it's B8(01010101), which is correct.

    Hmmm. I always thought 01010101 was 0x55. :-)

    Jon

  • "Looks like Mr. Torfs has a typo."

    I should have added that the typo is only in his commentary. As far as I know, the macros themselves are fine to use as-is (as-are?).

  • "I always thought 01010101 was 0x55."

    You're closer than I was. Taking 01010101 by itself, I came up with 266305.

  • if You absolutotally HAVE to do it

    #define bin00000001 0x01
    ...
    define bin11111111 0xff

    I do some 'binary' definitions this way

    in my .h file

    sfr S0_TMR2CN           = 0xc8;    // TIMER 2 CONTROL                              */
    sfr S1_TMR3CN           = 0xc8;    // TIMER 3 CONTROL
    sfr S2_TMR4CN           = 0xc8;    // TIMER 4 CONTROL
      sbit SB0_TMR2CN_TF      = 0xcf;
      sbit SB1_TMR3CN_TF      = 0xcf;
      sbit SB1_TMR3CN_TR      = 0xca;
      #define SM_TMRxCN_TF      0x80  // oflo/int
      #define SM_TMRxCN_EXF     0x40  // ext activate
      #define SM_TMRxCN_EXEN    0x08  // ext stimuli
      #define SM_TMRxCN_TR      0x04  // run control
      #define SM_TMRxCN_C_T     0x02  // 1 = counter 0=timer
      #define SM_TMRxCN_CP_RL   0x01  // 0 = reload, 1 = capture
    


    then in the .c file

    //S0_TMR2CN = 0 + SM_TMRxCN_TF + SM_TMRxCN_EXF + SM_TMRxCN_EXEN + SM_TMRxCN_TR + SM_TMRxCN_C_T + SM_TMRxCN_CP_RL;
      S2_TMR4CN = 0                                                 + SM_TMRxCN_TR                 + SM_TMRxCN_CP_RL;