// Proceed to the requested number of digits
	formatDecimal(d, uint64(di), !d0, roundUp, prec)
	// Adjust exponent
	d.dp -= q
}

// ryuFtoaFixed64 formats mant*(2^exp) with prec decimal digits.
func ryuFtoaFixed64(d *decimalSlice, mant uint64, exp int, prec int) {
	if prec > 18 {
		panic("ryuFtoaFixed64 called with prec > 18")
	}
	// Zero input.
	if mant == 0 {
		d.nd, d.dp = 0, 0
		return
	}
	// Renormalize to a 55-bit mantissa.

		var buf [24]byte
		if bitSize == 32 && digits <= 9 {
			digs.d = buf[:]
			ryuFtoaFixed32(&digs, uint32(mant), exp-int(flt.mantbits), digits)
			ok = true
		} else if digits <= 18 {
			digs.d = buf[:]
			ryuFtoaFixed64(&digs, mant, exp-int(flt.mantbits), digits)
			ok = true
		}
	}
	if !ok {
		return bigFtoa(dst, prec, fmt, neg, mant, exp, flt)
	}
	return formatDigits(dst, shortest, neg, digs, prec, fmt)
}