git: 162bdeaa7324 - stable/12 - [libm] Correct comments in s_cbrt[l].c
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Date: Sun, 07 Aug 2022 09:05:52 UTC
The branch stable/12 has been updated by dim:
URL: https://cgit.FreeBSD.org/src/commit/?id=162bdeaa7324c4c75b015530eac4bcbd6c58d639
commit 162bdeaa7324c4c75b015530eac4bcbd6c58d639
Author: Steve Kargl <kargl@FreeBSD.org>
AuthorDate: 2022-08-04 17:31:57 +0000
Commit: Dimitry Andric <dim@FreeBSD.org>
CommitDate: 2022-08-07 09:03:20 +0000
[libm] Correct comments in s_cbrt[l].c
Damian McGuckin <damianm at esi dot com dot au> noted that the accuracy
claims in the code for cbrt(3) and cbrtl(3) were incorrect. Fix the
comments to more accurately describe the accuracies.
PR: 265603
MFC after: 3 days
(cherry picked from commit 369ea0520a3061c07400d7cd32172efb6af39815)
---
lib/msun/src/s_cbrt.c | 2 +-
lib/msun/src/s_cbrtl.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/msun/src/s_cbrt.c b/lib/msun/src/s_cbrt.c
index 0e609e110d9a..4353d340a1ac 100644
--- a/lib/msun/src/s_cbrt.c
+++ b/lib/msun/src/s_cbrt.c
@@ -108,7 +108,7 @@ cbrt(double x)
r=x/s; /* error <= 0.5 ulps; |r| < |t| */
w=t+t; /* t+t is exact */
r=(r-t)/(w+r); /* r-t is exact; w+r ~= 3*t */
- t=t+t*r; /* error <= 0.5 + 0.5/3 + epsilon */
+ t=t+t*r; /* error <= (0.5 + 0.5/3) * ulp */
return(t);
}
diff --git a/lib/msun/src/s_cbrtl.c b/lib/msun/src/s_cbrtl.c
index 2236c0fa0348..b15c96ecde03 100644
--- a/lib/msun/src/s_cbrtl.c
+++ b/lib/msun/src/s_cbrtl.c
@@ -136,7 +136,7 @@ cbrtl(long double x)
r=x/s; /* error <= 0.5 ulps; |r| < |t| */
w=t+t; /* t+t is exact */
r=(r-t)/(w+r); /* r-t is exact; w+r ~= 3*t */
- t=t+t*r; /* error <= 0.5 + 0.5/3 + epsilon */
+ t=t+t*r; /* error <= (0.5 + 0.5/3) * ulp */
t *= v.e;
RETURNI(t);