runtime: introduce and consistently use setNsec for timespec

The general code for setting a timespec value sometimes used set_nsec
and sometimes used a combination of set_sec and set_nsec. Standardize
on a setNsec function that takes a number of nanoseconds and splits
them up to set the tv_sec and tv_nsec fields. Consistently mark
setNsec as go:nosplit, since it has to be that way on some systems
including Darwin and GNU/Linux. Consistently use timediv on 32-bit
systems to help stay within split-stack limits on processors that
don't have a 64-bit division instruction.

Change-Id: I6396bb7ddbef171a96876bdeaf7a1c585a6d725b
Reviewed-on: https://go-review.googlesource.com/c/go/+/167389
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

1 files changed, 3 insertions, 6 deletions

diff --git a/src/runtime/defs1_netbsd_386.go b/src/runtime/defs1_netbsd_386.go
index c26f417a02..3eae12eed0 100644
--- a/src/runtime/defs1_netbsd_386.go
+++ b/src/runtime/defs1_netbsd_386.go
@@ -106,12 +106,9 @@ type timespec struct {
 	tv_nsec int32
 }
 
-func (ts *timespec) set_sec(x int32) {
-	ts.tv_sec = int64(x)
-}
-
-func (ts *timespec) set_nsec(x int32) {
-	ts.tv_nsec = x
+//go:nosplit
+func (ts *timespec) setNsec(ns int64) {
+	ts.tv_sec = int64(timediv(ns, 1e9, &ts.tv_nsec))
 }
 
 type timeval struct {