Function III_requantize

modules/data/mp3/libmad/layer3.c:918–962

NAME: III_requantize() DESCRIPTION: requantize one (positive) value */

   DESCRIPTION:	requantize one (positive) value
*/
static
mad_fixed_t III_requantize(unsigned int value, signed int exp)
{
  mad_fixed_t requantized;
  signed int frac;
  struct fixedfloat power;

  stack(__FUNCTION__, __FILE__, __LINE__);
  frac = exp % 4;  /* assumes sign(frac) == sign(exp) */
  exp /= 4;

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstrict-aliasing"
  *(uint32_t*)&power = *(uint32_t*)&rq_table[value]; //memcpy_P(&power, &rq_table[value], sizeof(power)); // Avoid byte access to PROGMEM
#pragma GCC diagnostic pop
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wuninitialized"
  requantized = power.mantissa;
  exp += power.exponent;
#pragma GCC diagnostic pop

  if (exp < 0) {
    if (-exp >= (int)(sizeof(mad_fixed_t) * CHAR_BIT)) {
      /* underflow */
      requantized = 0;
    }
    else {
      requantized += 1L << (-exp - 1);
      requantized >>= -exp;
    }
  }
  else {
    if (exp >= 5) {
      /* overflow */
# if 0 && defined(DEBUG)
      fprintf(stderr, "requantize overflow (%f * 2^%d)\n",
              mad_f_todouble(requantized), exp);
# endif
      requantized = MAD_F_MAX;
    }
    else
      requantized <<= exp;
  }
  return frac ? mad_f_mul(requantized, root_table(3 + frac)) : requantized;
}

/* we must take care that sz >= bits and sz < sizeof(long) lest bits == 0 */
# define MASK(cache, sz, bits)	\