cmd/internal/obj/ppc64: support for decimal floating point instructions
1. Support for decimal arithmetic quad instructions of powerpc: DADDQ, DSUBQ, DMULQ
and DDIVQ.
2. Support for decimal compare ordered, unordered, quad instructions of powerpc:
DCMPU, DCMPO, DCMPUQ, and DCMPOQ.
Change-Id: I32a15a7f0a127b022b1f43d376e0ab0f7e9dd108
Cq-Include-Trybots: luci.golang.try:gotip-linux-ppc64_power10,gotip-linux-ppc64_power8,gotip-linux-ppc64le_power8,gotip-linux-ppc64le_power9,gotip-linux-ppc64le_power10
Reviewed-on: https://go-review.googlesource.com/c/go/+/623036
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Paul Murphy <murp@ibm.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Paul Murphy <murp@ibm.com> Reviewed-by: Cherry Mui <cherryyz@google.com>