1 files changed, 122 insertions, 0 deletions
diff --git a/src/cmd/internal/obj/s390x/rotate_test.go b/src/cmd/internal/obj/s390x/rotate_test.go
new file mode 100644
index 0000000..88421b1
--- /dev/null
+++ b/src/cmd/internal/obj/s390x/rotate_test.go
@@ -0,0 +1,122 @@
+// Copyright 2020 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.
+
+package s390x
+
+import (
+	"testing"
+)
+
+func TestRotateParamsMask(t *testing.T) {
+	tests := []struct {
+		start, end, amount uint8
+		inMask, outMask    uint64
+	}{
+		// start before end, no rotation
+		{start: 0, end: 63, amount: 0, inMask: ^uint64(0), outMask: ^uint64(0)},
+		{start: 1, end: 63, amount: 0, inMask: ^uint64(0) >> 1, outMask: ^uint64(0) >> 1},
+		{start: 0, end: 62, amount: 0, inMask: ^uint64(1), outMask: ^uint64(1)},
+		{start: 1, end: 62, amount: 0, inMask: ^uint64(3) >> 1, outMask: ^uint64(3) >> 1},
+
+		// end before start, no rotation
+		{start: 63, end: 0, amount: 0, inMask: 1<<63 | 1, outMask: 1<<63 | 1},
+		{start: 62, end: 0, amount: 0, inMask: 1<<63 | 3, outMask: 1<<63 | 3},
+		{start: 63, end: 1, amount: 0, inMask: 3<<62 | 1, outMask: 3<<62 | 1},
+		{start: 62, end: 1, amount: 0, inMask: 3<<62 | 3, outMask: 3<<62 | 3},
+
+		// rotation
+		{start: 32, end: 63, amount: 32, inMask: 0xffffffff00000000, outMask: 0x00000000ffffffff},
+		{start: 48, end: 15, amount: 16, inMask: 0xffffffff00000000, outMask: 0xffff00000000ffff},
+		{start: 0, end: 7, amount: -8 & 63, inMask: 0xff, outMask: 0xff << 56},
+	}
+	for i, test := range tests {
+		r := NewRotateParams(test.start, test.end, test.amount)
+		if m := r.OutMask(); m != test.outMask {
+			t.Errorf("out mask %v: want %#x, got %#x", i, test.outMask, m)
+		}
+		if m := r.InMask(); m != test.inMask {
+			t.Errorf("in mask %v: want %#x, got %#x", i, test.inMask, m)
+		}
+	}
+}
+
+func TestRotateParamsMerge(t *testing.T) {
+	tests := []struct {
+		// inputs
+		src  RotateParams
+		mask uint64
+
+		// results
+		in  *RotateParams
+		out *RotateParams
+	}{
+		{
+			src:  RotateParams{Start: 48, End: 15, Amount: 16},
+			mask: 0xffffffffffffffff,
+			in:   &RotateParams{Start: 48, End: 15, Amount: 16},
+			out:  &RotateParams{Start: 48, End: 15, Amount: 16},
+		},
+		{
+			src:  RotateParams{Start: 16, End: 47, Amount: 0},
+			mask: 0x00000000ffffffff,
+			in:   &RotateParams{Start: 32, End: 47, Amount: 0},
+			out:  &RotateParams{Start: 32, End: 47, Amount: 0},
+		},
+		{
+			src:  RotateParams{Start: 16, End: 47, Amount: 0},
+			mask: 0xffff00000000ffff,
+			in:   nil,
+			out:  nil,
+		},
+		{
+			src:  RotateParams{Start: 0, End: 63, Amount: 0},
+			mask: 0xf7f0000000000000,
+			in:   nil,
+			out:  nil,
+		},
+		{
+			src:  RotateParams{Start: 0, End: 63, Amount: 1},
+			mask: 0x000000000000ff00,
+			in:   &RotateParams{Start: 47, End: 54, Amount: 1},
+			out:  &RotateParams{Start: 48, End: 55, Amount: 1},
+		},
+		{
+			src:  RotateParams{Start: 32, End: 63, Amount: 32},
+			mask: 0xffff00000000ffff,
+			in:   &RotateParams{Start: 32, End: 47, Amount: 32},
+			out:  &RotateParams{Start: 48, End: 63, Amount: 32},
+		},
+		{
+			src:  RotateParams{Start: 0, End: 31, Amount: 32},
+			mask: 0x8000000000000000,
+			in:   nil,
+			out:  &RotateParams{Start: 0, End: 0, Amount: 32},
+		},
+		{
+			src:  RotateParams{Start: 0, End: 31, Amount: 32},
+			mask: 0x0000000080000000,
+			in:   &RotateParams{Start: 0, End: 0, Amount: 32},
+			out:  nil,
+		},
+	}
+
+	eq := func(x, y *RotateParams) bool {
+		if x == nil && y == nil {
+			return true
+		}
+		if x == nil || y == nil {
+			return false
+		}
+		return *x == *y
+	}
+
+	for _, test := range tests {
+		if r := test.src.InMerge(test.mask); !eq(r, test.in) {
+			t.Errorf("%v merged with %#x (input): want %v, got %v", test.src, test.mask, test.in, r)
+		}
+		if r := test.src.OutMerge(test.mask); !eq(r, test.out) {
+			t.Errorf("%v merged with %#x (output): want %v, got %v", test.src, test.mask, test.out, r)
+		}
+	}
+}