What are some tricks I can use with macros? [closed]

Answer 1

For embedded code, a nice trick from embeddedgurus.com enables you to handle binary values:

B8(01010101) // 85
B16(10101010,01010101) // 43,605
B32(10000000,11111111,10101010,01010101) // 2,164,238,93

This achieve similar goals as the previous response from @Ferruccio about BOOST_BINARY, although a bit expanded.

Here's the code (copy'n pasted, not tested, see link for more details)

// Internal Macros
#define HEX__(n) 0x##n##LU
#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-visible Macros
#define B8(d) ((unsigned char)B8__(HEX__(d)))
#define B16(dmsb,dlsb) (((unsigned short)B8(dmsb)<<8) + B8(dlsb))
#define B32(dmsb,db2,db3,dlsb) \
  (((unsigned long)B8(dmsb)<<24) \
  + ((unsigned long)B8(db2)<<16) \
  + ((unsigned long)B8(db3)<<8) \
  + B8(dlsb))

I like macros. So much fun when debugging !