float64 float64_round_to_int()

in nwfpe/softfloat.c [1863:1914]

• 50 lines of code
• 18 McCabe index (conditional complexity)

float64 float64_round_to_int( struct roundingData *roundData, float64 a )
{
    flag aSign;
    int16 aExp;
    bits64 lastBitMask, roundBitsMask;
    int8 roundingMode;
    float64 z;

    aExp = extractFloat64Exp( a );
    if ( 0x433 <= aExp ) {
        if ( ( aExp == 0x7FF ) && extractFloat64Frac( a ) ) {
            return propagateFloat64NaN( a, a );
        }
        return a;
    }
    if ( aExp <= 0x3FE ) {
        if ( (bits64) ( a<<1 ) == 0 ) return a;
        roundData->exception |= float_flag_inexact;
        aSign = extractFloat64Sign( a );
        switch ( roundData->mode ) {
         case float_round_nearest_even:
            if ( ( aExp == 0x3FE ) && extractFloat64Frac( a ) ) {
                return packFloat64( aSign, 0x3FF, 0 );
            }
            break;
         case float_round_down:
            return aSign ? LIT64( 0xBFF0000000000000 ) : 0;
         case float_round_up:
            return
            aSign ? LIT64( 0x8000000000000000 ) : LIT64( 0x3FF0000000000000 );
        }
        return packFloat64( aSign, 0, 0 );
    }
    lastBitMask = 1;
    lastBitMask <<= 0x433 - aExp;
    roundBitsMask = lastBitMask - 1;
    z = a;
    roundingMode = roundData->mode;
    if ( roundingMode == float_round_nearest_even ) {
        z += lastBitMask>>1;
        if ( ( z & roundBitsMask ) == 0 ) z &= ~ lastBitMask;
    }
    else if ( roundingMode != float_round_to_zero ) {
        if ( extractFloat64Sign( z ) ^ ( roundingMode == float_round_up ) ) {
            z += roundBitsMask;
        }
    }
    z &= ~ roundBitsMask;
    if ( z != a ) roundData->exception |= float_flag_inexact;
    return z;

}