79 строки
2,1 КиБ
Go
79 строки
2,1 КиБ
Go
// +build nxp,mk66f18
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package volatile
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import "unsafe"
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const registerBase = 0x40000000
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const registerEnd = 0x40100000
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const bitbandBase = 0x42000000
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const ptrBytes = unsafe.Sizeof(uintptr(0))
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//go:inline
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func bitbandAddress(reg uintptr, bit uint8) uintptr {
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if uintptr(bit) > ptrBytes*8 {
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panic("invalid bit position")
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}
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if reg < registerBase || reg >= registerEnd {
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panic("register is out of range")
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}
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return (reg-registerBase)*ptrBytes*8 + uintptr(bit)*ptrBytes + bitbandBase
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}
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// Special types that causes loads/stores to be volatile (necessary for
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// memory-mapped registers).
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type BitRegister struct {
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Reg uint32
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}
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// Get returns the of the mapped register bit. It is the volatile equivalent of:
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//
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// *r.Reg
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//
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//go:inline
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func (r *BitRegister) Get() bool {
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return LoadUint32(&r.Reg) != 0
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}
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// Set sets the mapped register bit. It is the volatile equivalent of:
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//
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// *r.Reg = 1
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//
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//go:inline
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func (r *BitRegister) Set(v bool) {
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var i uint32
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if v {
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i = 1
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}
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StoreUint32(&r.Reg, i)
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}
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// Bit maps bit N of register R to the corresponding bitband address. Bit panics
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// if R is not an AIPS or GPIO register or if N is out of range (greater than
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// the number of bits in a register minus one).
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//
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// go:inline
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func (r *Register8) Bit(bit uint8) *BitRegister {
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ptr := bitbandAddress(uintptr(unsafe.Pointer(&r.Reg)), bit)
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return (*BitRegister)(unsafe.Pointer(ptr))
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}
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// Bit maps bit N of register R to the corresponding bitband address. Bit panics
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// if R is not an AIPS or GPIO register or if N is out of range (greater than
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// the number of bits in a register minus one).
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//
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// go:inline
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func (r *Register16) Bit(bit uint8) *BitRegister {
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ptr := bitbandAddress(uintptr(unsafe.Pointer(&r.Reg)), bit)
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return (*BitRegister)(unsafe.Pointer(ptr))
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}
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// Bit maps bit N of register R to the corresponding bitband address. Bit panics
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// if R is not an AIPS or GPIO register or if N is out of range (greater than
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// the number of bits in a register minus one).
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//
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// go:inline
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func (r *Register32) Bit(bit uint8) *BitRegister {
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ptr := bitbandAddress(uintptr(unsafe.Pointer(&r.Reg)), bit)
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return (*BitRegister)(unsafe.Pointer(ptr))
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}
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