export function nextAfterF32()

in src/webgpu/util/math.ts [191:246]

• 43 lines of code
• 17 McCabe index (conditional complexity)

export function nextAfterF32(val: number, dir: NextDirection, mode: FlushMode): number {
  if (Number.isNaN(val)) {
    return val;
  }

  if (val === Number.POSITIVE_INFINITY) {
    return kValue.f32.positive.infinity;
  }

  if (val === Number.NEGATIVE_INFINITY) {
    return kValue.f32.negative.infinity;
  }

  assert(
    val <= kValue.f32.positive.max && val >= kValue.f32.negative.min,
    `${val} is not in the range of f32`
  );

  val = mode === 'flush' ? flushSubnormalNumberF32(val) : val;

  // -/+0 === 0 returns true
  if (val === 0) {
    if (dir === 'positive') {
      return mode === 'flush' ? kValue.f32.positive.min : kValue.f32.positive.subnormal.min;
    } else {
      return mode === 'flush' ? kValue.f32.negative.max : kValue.f32.negative.subnormal.max;
    }
  }

  nextAfterF32Float[0] = val; // This quantizes from number (f64) to f32
  if (
    (dir === 'positive' && nextAfterF32Float[0] <= val) ||
    (dir === 'negative' && nextAfterF32Float[0] >= val)
  ) {
    // val is either f32 precise or quantizing rounded in the opposite direction
    // from what is needed, so need to calculate the value in the correct
    // direction.
    const is_positive = (nextAfterF32Int[0] & 0x80000000) === 0;
    if (is_positive === (dir === 'positive')) {
      nextAfterF32Int[0] += 1;
    } else {
      nextAfterF32Int[0] -= 1;
    }
  }

  // Checking for overflow
  if ((nextAfterF32Int[0] & 0x7f800000) === 0x7f800000) {
    if (dir === 'positive') {
      return kValue.f32.positive.infinity;
    } else {
      return kValue.f32.negative.infinity;
    }
  }

  return mode === 'flush' ? flushSubnormalNumberF32(nextAfterF32Float[0]) : nextAfterF32Float[0];
}