Микроконтроллеры

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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