10 Dec
2008
10 Dec
'08
11:24 p.m.
On Dec 10, 2008, at 4:16 PM, Johan Råde wrote:
Gordon Woodhull wrote:
On Dec 10, 2008, at 7:24 AM, Johan Råde wrote:
Is the following true: if x and y satisfy x <= y (or x >= y) then they will still do so after any truncation from 80 to 64 bits? Nope, as John pointed out later in his message, if the test is x<=y and x is just slightly greater than y, then x can flip either way.
The statement is "x <= y before truncation implies x <= y after truncation". (Note the word "implies", not "equivalent to".) The example you mention is not a counter-example to that statement.
Ooops, you are quite right. In other words, perhaps truncation can merge two values but it can't switch them, if I understand you this time. I hope this is the case.