github.com/dolthub/swiss@v0.2.2-0.20240312182618-f4b2babd2bc1/bits_amd64.go (about)

     1  // Copyright 2023 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  //go:build amd64 && !nosimd
    16  
    17  package swiss
    18  
    19  import (
    20  	"math/bits"
    21  	_ "unsafe"
    22  
    23  	"github.com/dolthub/swiss/simd"
    24  )
    25  
    26  const (
    27  	groupSize       = 16
    28  	maxAvgGroupLoad = 14
    29  )
    30  
    31  type bitset uint16
    32  
    33  func metaMatchH2(m *metadata, h h2) bitset {
    34  	b := simd.MatchMetadata((*[16]int8)(m), int8(h))
    35  	return bitset(b)
    36  }
    37  
    38  func metaMatchEmpty(m *metadata) bitset {
    39  	b := simd.MatchMetadata((*[16]int8)(m), empty)
    40  	return bitset(b)
    41  }
    42  
    43  func nextMatch(b *bitset) (s uint32) {
    44  	s = uint32(bits.TrailingZeros16(uint16(*b)))
    45  	*b &= ^(1 << s) // clear bit |s|
    46  	return
    47  }