add Apache 2.0 license header

Author: dank-openai

xls/dslx/stdlib/round.x

@@ -1,5 +1,3 @@
-#![feature(type_inference_v2)]
-
 // Copyright 2025 The XLS Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -14,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#![feature(type_inference_v2)]
+
 // Implements rounding for all rounding modes defined by the IEEE 754 standard.
 //
 // It handles unsigned, signed (two's complement), and sign-and-magnitude values.

xls/dslx/stdlib/tests/gen_round_tests.py

@@ -1,3 +1,17 @@
+# Copyright 2025 The XLS Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 """Generate DSLX round() tests.
 
 This script produces a comprehensive set of DSLX tests that exercise the
@@ -31,8 +45,8 @@
 
 
 class RoundingMode(Enum):
-  RNE = auto()  # convergent / bankers-rounding (nearest, ties-to-even)
-  RNA = auto()  # away from zero
+  RNE = auto()  # nearest, ties-to-even
+  RNA = auto()  # nearest, ties away from zero
   RTZ = auto()  # towards zero
   RTN = auto()  # towards -∞
   RTP = auto()  # towards +∞

xls/dslx/stdlib/tests/round_tests.x

@@ -1,3 +1,17 @@
+// Copyright 2025 The XLS Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 #![feature(type_inference_v2)]
 
 import std;