From d6294c3c4304751f89b65db96c3edaaf3dd6de18 Mon Sep 17 00:00:00 2001 From: lkcl Date: Sun, 9 Oct 2022 22:31:53 +0100 Subject: [PATCH] --- openpower/sv/rfc/ls002/discussion.mdwn | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/openpower/sv/rfc/ls002/discussion.mdwn b/openpower/sv/rfc/ls002/discussion.mdwn index 7abd96221..b95d8cef9 100644 --- a/openpower/sv/rfc/ls002/discussion.mdwn +++ b/openpower/sv/rfc/ls002/discussion.mdwn @@ -132,7 +132,11 @@ as a critical means of bootstrapping (constructing 64 bit addresses) What about fsub FRT,FRA,FRA? ** -That doesn't actually clear FRT to zero because NaN - NaN = Inf - Inf = NaN, not zero. Also, with round to -inf, 0 - 0 produces -0, not 0. +That doesn't actually clear FRT to zero because `NaN - NaN` and +`Inf - Inf` both equal `NaN`, not zero. Also, with "round to -inf", +0 - 0 produces -0, not 0. Thus use of `fsub` is critically +dependent on the contents of registers and status flags, where +`flis` is not. ** 5. "FRS" for both instructions should be changed to "FRT". ("FRS" normally -- 2.30.2