U32-to-U8 conversion

/*
 * U32TO8_BIG(c, v) stores the 32-bit-value v in big-endian convention
 * into the unsigned char array pointed to by c.
 */
#define U32TO8_BIG(c, v)    do { \
  u32 x = (v); \
  u8 *d = (c); \
  d[0] = T8(x >> 24); \
  d[1] = T8(x >> 16); \
  d[2] = T8(x >> 8); \
  d[3] = T8(x); \
 } while (0)

/*
 * U32TO8_LITTLE(c, v) stores the 32-bit-value v in little-endian convention
 * into the unsigned char array pointed to by c.
 */
#define U32TO8_LITTLE(c, v)    do { \
  u32 x = (v); \
  u8 *d = (c); \
  d[0] = T8(x); \
  d[1] = T8(x >> 8); \
  d[2] = T8(x >> 16); \
  d[3] = T8(x >> 24); \
 } while (0)

[C Programming] Difference between const int* and int* const

const int* - a variable pointer pointing to a constant integer.

int* const - a constant pointer pointing to a variable integer.

E.g.

int i = 7;

const int* p = &i;

*p = 8; //ERROR!

* The trick is to read from right to left. :)