PLS@cup.portal.com (Paul L Schauble) (11/05/88)
Looking through some old paperwork brought back to mind a very old machine I used to work on. This machine contained an interesting feature. It has a register that stored the maximum postnormalizing shift performed. This was updated for each floating point add or subtract. There was an instruction to store and clear this register. This seems like a useful feature. You could run a data item through an algorithm, then store this register and see what precision was actually maintained through the algorithm. My question is that I haven't seen this feature or any equivalent in any modern hardware. Why? Has experience shown it to be useless? Is there some non-obvious problem with it? ++PLS