Hexadecimal, BCD, and decimal conversion

In the design of embedded software, we often encounter hexadecimal,
BCD
The conversion between the Code and the decimal number.
M1
Card applications involve a large number of hexadecimal,
BCD
Conversion between code and decimal. The author
BCD
Code, hexadecimal
Rights can be easily exchanged between them.

 # Include <stdio. h> <br/> # include <string. h> </P> <p> /////////////////////////////// /// // <br/> // function: binary inversion <br/> // input: const unsigned char * SRC binary data <br/> // int length the length of the binary data to be converted <br/> // output: unsigned char * the binary data after DST is reversed <br/> // return: 0 success <br/> //////////////////////////// /// // <br/> int convert (unsigned char * DST, const Unsigned char * SRC, int length) <br/>{< br/> int I; </P> <p> for (I = 0; I <length; I ++) <br/>{< br/> DST [I] = SRC [I] ^ 0xff; <br/>}< br/> return 0; <br/>}</P> <p> //////////////////////////// /// // <br/> // function: convert hexadecimal to decimal <br/> // input: const unsigned char * hex hexadecimal data to be converted <br/> // int length hexadecimal Data Length <br/> // output: <br/> // return: decimal data after int rslt conversion <br/> // <br/> // Train of thought: the range of the decimal number represented by each character bit in hexadecimal format is 0 ~ 255, in hexadecimal format: 256 <br/> // shifts 8 bits to the left (<8) equivalent value multiplied by 256 <br/> /////////////////////////// //// // <br/> unsigned long hextodec (const unsigned char * hex, int length) <br/>{< br/> int I; <br/> unsigned long rslt = 0; </P> <p> for (I = 0; I <length; I ++) <br/> {<br/> rslt + = (unsigned long) (hex [I]) <(8 * (length-1-i )); </P> <p >}</P> <p> return rslt; <br/>}</P> <p> //////////////////////////// ///// /// // <Br/> // function: convert decimal to hexadecimal <br/> // input: int dec decimal data to be converted <br/> // length of the hexadecimal data after int length conversion <br/> // output: unsigned char * hex converted hexadecimal data <br/> // return: 0 success <br/> // train of thought: the principle is the same as that in hexadecimal notation <br/> ///////////////////////////// /// // <br/> int dectohex (INT Dec, unsigned char * hex, int length) <br/>{< br/> int I; </P> <p> for (I = length-1; I >= 0; I --) <br/>{< br/> hex [I] = (Dec % 256) & 0xff; <br/> DEC/= 256; <br/>}</P> <p> return 0; <br/>}</P> <p> //////////////////////////// /// // <br/>/ /function: request permission <br/> // enter: int base number <br/> // int times weight level <br/> // output: <br/> // return: unsigned long current data bit permission <br/> //////////////////////// /// // <br/> unsigned long power (INT base, int times) <br/>{< br/> int I; <br/> unsigned long rslt = 1; </P> <p> for (I = 0; I <times; I ++) <br/> rslt * = base; </P> <p> return rslt; <br/>}</P> <p> //////////////////////////// /// // <br/>/ /function: convert BCD to 10 hexadecimal <br/> // enter: const unsigned char * BCD code to be converted <br/> // int length BCD code Data Length <br/> // output: <br/> // return: Unsigned long current data bit permission <br/> // <Br/> // train of thought: compress the BCD code in decimal format from 0 ~ 99, decimal: 100 <br/> // first, calculate the decimal value represented by each character, then multiply the value by <br/> ///////////////////////////////// //////////////////// <br/> unsigned long bcdtodec (const unsigned char * BCD, int length) <br/>{< br/> int I, TMP; <br/> unsigned long dec = 0; </P> <p> for (I = 0; I <length; I ++) <br/>{< br/> TMP = (BCD [I]> 4) & 0x0f) * 10 + (BCD [I] & 0x0f); <br/> dec + = TMP * power (100, length-1-i ); <br/>}</P> <p> return Dec; <br/>}</P> <p> //////////////////////////// /// // <br/>/ /function: decimal to BCD code <br/> // enter: int dec decimal data to be converted <br/> // int length BCD code Data Length <br/> // output: unsigned char * BCD converted BCD code <br/> // return: 0 success <br/> // train of thought: same principle as BCD code to decimal <br/> //////////////////////// /// // <br/> int dectobcd (INT Dec, unsigned char * BCD, int length) <br/>{< br/> int I; <br/> int temp; </P> <p> for (I = length-1; I> = 0; I --) <br/> {<br/> temp = dec % 100; <br/> BCD [I] = (temp/10) <4) + (TEMP % 10) & 0x0f); <br/> DEC/= 100; <br/>}</P> <p> return 0; <br/>}< br/> // --------------- function information -------------------------------------- <br/> // number of letters: bcdtodec <br/> // Function Description: Convert the BCD code to a decimal code <br/> // entry parameter: temp: converted BCD code <br/> // return: converted decimal code <br/> // OPERATOR: <br/> // Date: 2006.11.24 <br/> // description: <br/> // optional <br/> uint8 bcdtodec (uint8 temp) <br/>{< br/> return (temp/16) * 10 + TEMP % 16); <br/>}</P> <p> // ------------- function information ------------------------------------------ <br/> // number of letters: dectobcd <br/> // Function Description: Convert hexadecimal code to BCD code. <br/> // entry parameter: temp: converted decimal code <br/> // return: converted BCD code <br/> // OPERATOR: <br/> // Date: 2006.11.24 <br/> // Description: <br/> // optional <br/> uint8 dectobcd (uint8 temp) <br/>{< br/> return (temp/10) * 16 + TEMP % 10); <br/>}< br/>