internal/abi: define riscv64 register ABI constants

Add the riscv64 register ABI constants and allow regabi
value to be set for riscv64

Change-Id: I3ce98bf9a29d2acc00f92650b27bc59884ed62ad
Reviewed-on: https://go-review.googlesource.com/c/go/+/359336
Trust: mzh <mzh@golangcn.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: mzh <mzh@golangcn.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/internal/abi/abi_riscv64.go b/src/internal/abi/abi_riscv64.go
new file mode 100644 (file)
index 0000000..1656820
--- /dev/null
+++ b/src/internal/abi/abi_riscv64.go
@@ -0,0 +1,19 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build goexperiment.regabiargs
+
+package abi
+
+const (
+       // See abi_generic.go.
+
+       // X8 - X23
+       IntArgRegs = 16
+
+       // F8 - F23.
+       FloatArgRegs = 16
+
+       EffectiveFloatRegSize = 8
+)