How to use binary numbers directly in Keil C51

In Keil C51, numbers cannot be assigned directly in binary form, although it is possible in 8051 assembly. Although binary numbers are long to write and prone to errors, because they are written bit by bit, programmers can clearly see the status of each bit, which is more intuitive. Therefore, many people miss 8051 assembly and want to use binary in C51. If I am not mistaken, the person who searched this blog is probably looking for this solution. The following two methods are both good choices.

Method 1:

Create a header file to list all binary number macro definitions. Use the macro definitions directly when needed. The header file definition is: binary (right click >> "Save Target As" >> Download).

Method 2:

Make a macro definition with parameters to convert the input binary-like number into the corresponding hexadecimal number. The entire definition and usage example are shown below. You can use it directly. If you want to study the principle but don’t understand the macro definition with parameters, please refer to the chapter on preprocessing commands in Tan Haoqiang’s "C Programming" (the third edition is on P204-P211).

#define LongToBin(n)

(

((n >> 21) & 0x80) |

((n >> 18) & 0x40) |

((n >> 15) & 0x20) |

((n >> 12) & 0x10) |

((n >> 9) & 0x08) |

((n >> 6) & 0x04) |

((n >> 3) & 0x02) |

((n ) & 0x01)

)

#define Bin(n) LongToBin(0x##n##l)

void main(void)

{

unisigned char c;

c = Bin(10101001); //equivalent to c = 0xA9

}

Backslash is used in the above preprocessing instructions. Here is an explanation: each prepared statement always starts with the "#" character and cannot exceed one line. Once a newline is encountered, the statement is considered to have ended. The only way to extend a prepared statement to multiple lines is to add a backslash ('') before the newline.