result of pow2_x is never more precise than double

3 results were exact to double the precision

20 largest ulp errors (stored in a double)
   0.50034 ulp for pow2_x(0.558003740900228307) = 1.47223067964920462)
   0.50029 ulp for pow2_x(-1015.50747564461142) = 2.00349844623462782e-306)
   0.50027 ulp for pow2_x(1016.65741438262501) = 1.10758494359601731e+306)
   0.50027 ulp for pow2_x(6.78795284350048345) = 110.503851465989669)
   0.50026 ulp for pow2_x(5.23012057299979283) = 37.5338551300854988)
   0.50025 ulp for pow2_x(418.252062540454062) = 8.06151326617881752e+125)
   0.50025 ulp for pow2_x(0.648630719800006195) = 1.56767958485623859)
   0.50025 ulp for pow2_x(-1020.71061166819266) = 5.43862350532862126e-308)
   0.50025 ulp for pow2_x(397.391652719998945) = 4.23455224242109544e+119)
   0.50025 ulp for pow2_x(1019.31756679378202) = 7.00104246931987101e+306)
   0.50024 ulp for pow2_x(-1018.43343033206963) = 2.63626390281147923e-307)
   0.50024 ulp for pow2_x(5.5990533549969026) = 48.4711146756388871)
   0.50024 ulp for pow2_x(5.70382075299969848) = 52.1220077586316677)
   0.50024 ulp for pow2_x(-1020.71061166777201) = 5.43862350691434076e-308)
   0.50023 ulp for pow2_x(452.55022194038628) = 1.70290863800875213e+136)
   0.50023 ulp for pow2_x(6.458895535000023) = 87.9673066067297498)
   0.50023 ulp for pow2_x(6.78795284349951089) = 110.503851465915176)
   0.50023 ulp for pow2_x(-1019.2213247151559) = 1.52689453383280618e-307)
   0.50022 ulp for pow2_x(0.363307369700009208) = 1.28637151882966805)
   0.50022 ulp for pow2_x(0.598293376599951521) = 1.51392462303019615)

<tr><td align=left><a href=pow2_x.res>pow2_x</a></td><td align=right>1467</td><td align=right>0.50034</td><td>0.558003740900228307</td><td>1.47223067964920462</td></tr>