fromHalfFloat static method

dynamic fromHalfFloat(num value)

Implementation

static fromHalfFloat(num value) {
  final val = value.toInt();
  final m = val >> 10;
  final uint32View = Uint32List( 4 );
  final mantissaTable = Uint32List( 2048 );
  final exponentTable = Uint32List( 64 );
  final offsetTable = Uint32List( 64 );

  for (int i = 1; i < 1024; ++ i ) {
    int m = i << 13; // zero pad mantissa bits
    int e = 0; // zero exponent

    // normalized
    while ( ( m & 0x00800000 ) == 0 ) {
      m <<= 1;
      e -= 0x00800000; // decrement exponent
    }

    m &= ~ 0x00800000; // clear leading 1 bit
    e += 0x38800000; // adjust bias

    mantissaTable[ i ] = m | e;
  }

  for (int i = 1024; i < 2048; ++ i ) {
    mantissaTable[ i ] = 0x38000000 + ( ( i - 1024 ) << 13 );
  }

  for (int i = 1; i < 31; ++ i ) {
    exponentTable[ i ] = i << 23;
  }

  exponentTable[ 31 ] = 0x47800000;
  exponentTable[ 32 ] = 0x80000000;

  for (int i = 33; i < 63; ++ i ) {
    exponentTable[ i ] = 0x80000000 + ( ( i - 32 ) << 23 );
  }

  exponentTable[ 63 ] = 0xc7800000;

  for (int i = 1; i < 64; ++ i ) {
    if ( i != 32 ) {
      offsetTable[ i ] = 1024;
    }
  }

  uint32View[ 0 ] = mantissaTable[offsetTable[ m ] + ( val & 0x3ff ) ] + exponentTable[ m ];
  return uint32View.buffer.asFloat32List();
}