Documentation
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Overview ¶
Package volatile provides definitions for volatile loads and stores. These are implemented as compiler builtins.
The load operations load a volatile value. The store operations store to a volatile value. The compiler will emit exactly one load or store operation when possible and will not reorder volatile operations. However, the compiler may move other operations across load/store operations, so make sure that all relevant loads/stores are done in a volatile way if this is a problem.
These loads and stores are commonly used to read/write values from memory mapped peripheral devices. They do not provide atomicity, use the sync/atomic package for that.
For more details: https://llvm.org/docs/LangRef.html#volatile-memory-accesses and https://blog.regehr.org/archives/28.
Index ¶
- func LoadUint16(addr *uint16) (val uint16)
- func LoadUint32(addr *uint32) (val uint32)
- func LoadUint64(addr *uint64) (val uint64)
- func LoadUint8(addr *uint8) (val uint8)
- func StoreUint16(addr *uint16, val uint16)
- func StoreUint32(addr *uint32, val uint32)
- func StoreUint64(addr *uint64, val uint64)
- func StoreUint8(addr *uint8, val uint8)
- type Register16
- type Register32
- type Register64
- type Register8
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func LoadUint16 ¶
LoadUint16 loads the volatile value *addr.
func LoadUint32 ¶
LoadUint32 loads the volatile value *addr.
func LoadUint64 ¶ added in v0.14.0
LoadUint64 loads the volatile value *addr.
func StoreUint16 ¶
StoreUint16 stores val to the volatile value *addr.
func StoreUint32 ¶
StoreUint32 stores val to the volatile value *addr.
func StoreUint64 ¶ added in v0.14.0
StoreUint64 stores val to the volatile value *addr.
func StoreUint8 ¶
StoreUint8 stores val to the volatile value *addr.
Types ¶
type Register16 ¶ added in v0.7.0
type Register16 struct {
Reg uint16
}
func (*Register16) ClearBits ¶ added in v0.7.0
func (r *Register16) ClearBits(value uint16)
ClearBits reads the register, clears the given bits, and writes it back. It is the volatile equivalent of:
r.Reg &^= value
func (*Register16) Get ¶ added in v0.7.0
func (r *Register16) Get() uint16
Get returns the value in the register. It is the volatile equivalent of:
*r.Reg
func (*Register16) HasBits ¶ added in v0.7.0
func (r *Register16) HasBits(value uint16) bool
HasBits reads the register and then checks to see if the passed bits are set. It is the volatile equivalent of:
(*r.Reg & value) > 0
func (*Register16) ReplaceBits ¶ added in v0.13.0
func (r *Register16) ReplaceBits(value uint16, mask uint16, pos uint8)
ReplaceBits is a helper to simplify setting multiple bits high and/or low at once. It is the volatile equivalent of:
r.Reg = (r.Reg & ^(mask << pos)) | value << pos
func (*Register16) Set ¶ added in v0.7.0
func (r *Register16) Set(value uint16)
Set updates the register value. It is the volatile equivalent of:
*r.Reg = value
func (*Register16) SetBits ¶ added in v0.7.0
func (r *Register16) SetBits(value uint16)
SetBits reads the register, sets the given bits, and writes it back. It is the volatile equivalent of:
r.Reg |= value
type Register32 ¶ added in v0.7.0
type Register32 struct {
Reg uint32
}
func (*Register32) ClearBits ¶ added in v0.7.0
func (r *Register32) ClearBits(value uint32)
ClearBits reads the register, clears the given bits, and writes it back. It is the volatile equivalent of:
r.Reg &^= value
func (*Register32) Get ¶ added in v0.7.0
func (r *Register32) Get() uint32
Get returns the value in the register. It is the volatile equivalent of:
*r.Reg
func (*Register32) HasBits ¶ added in v0.7.0
func (r *Register32) HasBits(value uint32) bool
HasBits reads the register and then checks to see if the passed bits are set. It is the volatile equivalent of:
(*r.Reg & value) > 0
func (*Register32) ReplaceBits ¶ added in v0.13.0
func (r *Register32) ReplaceBits(value uint32, mask uint32, pos uint8)
ReplaceBits is a helper to simplify setting multiple bits high and/or low at once. It is the volatile equivalent of:
r.Reg = (r.Reg & ^(mask << pos)) | value << pos
func (*Register32) Set ¶ added in v0.7.0
func (r *Register32) Set(value uint32)
Set updates the register value. It is the volatile equivalent of:
*r.Reg = value
func (*Register32) SetBits ¶ added in v0.7.0
func (r *Register32) SetBits(value uint32)
SetBits reads the register, sets the given bits, and writes it back. It is the volatile equivalent of:
r.Reg |= value
type Register64 ¶ added in v0.14.0
type Register64 struct {
Reg uint64
}
func (*Register64) ClearBits ¶ added in v0.14.0
func (r *Register64) ClearBits(value uint64)
ClearBits reads the register, clears the given bits, and writes it back. It is the volatile equivalent of:
r.Reg &^= value
func (*Register64) Get ¶ added in v0.14.0
func (r *Register64) Get() uint64
Get returns the value in the register. It is the volatile equivalent of:
*r.Reg
func (*Register64) HasBits ¶ added in v0.14.0
func (r *Register64) HasBits(value uint64) bool
HasBits reads the register and then checks to see if the passed bits are set. It is the volatile equivalent of:
(*r.Reg & value) > 0
func (*Register64) ReplaceBits ¶ added in v0.14.0
func (r *Register64) ReplaceBits(value uint64, mask uint64, pos uint8)
ReplaceBits is a helper to simplify setting multiple bits high and/or low at once. It is the volatile equivalent of:
r.Reg = (r.Reg & ^(mask << pos)) | value << pos
func (*Register64) Set ¶ added in v0.14.0
func (r *Register64) Set(value uint64)
Set updates the register value. It is the volatile equivalent of:
*r.Reg = value
func (*Register64) SetBits ¶ added in v0.14.0
func (r *Register64) SetBits(value uint64)
SetBits reads the register, sets the given bits, and writes it back. It is the volatile equivalent of:
r.Reg |= value
type Register8 ¶ added in v0.7.0
type Register8 struct {
Reg uint8
}
Special types that causes loads/stores to be volatile (necessary for memory-mapped registers).
func (*Register8) ClearBits ¶ added in v0.7.0
ClearBits reads the register, clears the given bits, and writes it back. It is the volatile equivalent of:
r.Reg &^= value
func (*Register8) Get ¶ added in v0.7.0
Get returns the value in the register. It is the volatile equivalent of:
*r.Reg
func (*Register8) HasBits ¶ added in v0.7.0
HasBits reads the register and then checks to see if the passed bits are set. It is the volatile equivalent of:
(*r.Reg & value) > 0
func (*Register8) ReplaceBits ¶ added in v0.13.0
ReplaceBits is a helper to simplify setting multiple bits high and/or low at once. It is the volatile equivalent of:
r.Reg = (r.Reg & ^(mask << pos)) | value << pos
Source Files