blob: 867d309a3d987065aed4c3b2c65534e1b9a8fe40 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
// Copyright 2021 The gVisor 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.
// Package fpu provides basic floating point helpers.
package fpu
import (
"fmt"
"reflect"
)
// State represents floating point state.
//
// This is a simple byte slice, but may have architecture-specific methods
// attached to it.
type State []byte
// ErrLoadingState indicates a failed restore due to unusable floating point
// state.
type ErrLoadingState struct {
// supported is the supported floating point state.
supportedFeatures uint64
// saved is the saved floating point state.
savedFeatures uint64
}
// Error returns a sensible description of the restore error.
func (e ErrLoadingState) Error() string {
return fmt.Sprintf("floating point state contains unsupported features; supported: %#x saved: %#x", e.supportedFeatures, e.savedFeatures)
}
// alignedBytes returns a slice of size bytes, aligned in memory to the given
// alignment. This is used because we require certain structures to be aligned
// in a specific way (for example, the X86 floating point data).
func alignedBytes(size, alignment uint) []byte {
data := make([]byte, size+alignment-1)
offset := uint(reflect.ValueOf(data).Index(0).Addr().Pointer() % uintptr(alignment))
if offset == 0 {
return data[:size:size]
}
return data[alignment-offset:][:size:size]
}
|
