mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-13 18:40:45 +01:00
48 lines
1.3 KiB
Go
48 lines
1.3 KiB
Go
|
// Copyright 2019 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
|
||
|
|
|
||
|
|
// RotateParams represents the immediates required for a "rotate
|
||
|
|
// then ... selected bits instruction".
|
||
|
|
//
|
||
|
|
// The Start and End values are the indexes that represent
|
||
|
|
// the masked region. They are inclusive and are in big-
|
||
|
|
// endian order (bit 0 is the MSB, bit 63 is the LSB). They
|
||
|
|
// may wrap around.
|
||
|
|
//
|
||
|
|
// Some examples:
|
||
|
|
//
|
||
|
|
// Masked region | Start | End
|
||
|
|
// --------------------------+-------+----
|
||
|
|
// 0x00_00_00_00_00_00_00_0f | 60 | 63
|
||
|
|
// 0xf0_00_00_00_00_00_00_00 | 0 | 3
|
||
|
|
// 0xf0_00_00_00_00_00_00_0f | 60 | 3
|
||
|
|
//
|
||
|
|
// The Amount value represents the amount to rotate the
|
||
|
|
// input left by. Note that this rotation is performed
|
||
|
|
// before the masked region is used.
|
||
|
|
type RotateParams struct {
|
||
|
|
Start uint8 // big-endian start bit index [0..63]
|
||
|
|
End uint8 // big-endian end bit index [0..63]
|
||
|
|
Amount uint8 // amount to rotate left
|
||
|
|
}
|
||
|
|
|
||
|
|
func NewRotateParams(start, end, amount int64) RotateParams {
|
||
|
|
if start&^63 != 0 {
|
||
|
|
panic("start out of bounds")
|
||
|
|
}
|
||
|
|
if end&^63 != 0 {
|
||
|
|
panic("end out of bounds")
|
||
|
|
}
|
||
|
|
if amount&^63 != 0 {
|
||
|
|
panic("amount out of bounds")
|
||
|
|
}
|
||
|
|
return RotateParams{
|
||
|
|
Start: uint8(start),
|
||
|
|
End: uint8(end),
|
||
|
|
Amount: uint8(amount),
|
||
|
|
}
|
||
|
|
}
|