E.g. known errors: x = 0x1.000002c5e2e99p+0, y = 0x1.c9eee35374af6p+31 had an error of 639 ULP and is now correctly rounded. x = 0x1.fffffd2e3e669p-1, y = 0x1.344c9823eb66cp+32 had an error of 428 ULP and is now correctly rounded.