github.com/apache/arrow/go/v10@v10.0.1/parquet/internal/utils/bit_packing_arm64.go (about)

     1  // Licensed to the Apache Software Foundation (ASF) under one
     2  // or more contributor license agreements.  See the NOTICE file
     3  // distributed with this work for additional information
     4  // regarding copyright ownership.  The ASF licenses this file
     5  // to you under the Apache License, Version 2.0 (the
     6  // "License"); you may not use this file except in compliance
     7  // with the License.  You may obtain a copy of the License at
     8  //
     9  // http://www.apache.org/licenses/LICENSE-2.0
    10  //
    11  // Unless required by applicable law or agreed to in writing, software
    12  // distributed under the License is distributed on an "AS IS" BASIS,
    13  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14  // See the License for the specific language governing permissions and
    15  // limitations under the License.
    16  
    17  // +build !noasm
    18  
    19  package utils
    20  
    21  import (
    22  	"io"
    23  	"os"
    24  	"strings"
    25  )
    26  import "golang.org/x/sys/cpu"
    27  
    28  var unpack32 func(io.Reader, []uint32, int) int = unpack32Default
    29  
    30  func init() {
    31          cpu.ARM64.HasASIMD = false
    32          cpu.ARM64.HasAES = false
    33          cpu.ARM64.HasPMULL = false
    34          // Added ability to enable extension via environment:
    35  	if ext, ok := os.LookupEnv("ARM_ENABLE_EXT"); ok {
    36  		exts := strings.Split(ext, ",")
    37  
    38  		for _, x := range exts {
    39  			switch x {
    40  			case "NEON":
    41  				cpu.ARM64.HasASIMD = true
    42  			case "AES":
    43  				cpu.ARM64.HasAES = true
    44  			case "PMULL":
    45  				cpu.ARM64.HasPMULL = true
    46  			default:
    47  			}
    48  		}
    49  	}
    50  	if cpu.ARM64.HasASIMD {
    51  		unpack32 = unpack32NEON
    52  	} else { // default to the pure go implementation if no avx2 available
    53  		unpack32 = unpack32Default
    54  	}
    55  }
    56