github.com/tinygo-org/tinygo@v0.31.3-0.20240404173401-90b0bf646c27/src/runtime/interrupt/interrupt_avr.go (about)

     1  //go:build avr
     2  
     3  package interrupt
     4  
     5  import "device"
     6  
     7  // State represents the previous global interrupt state.
     8  type State uint8
     9  
    10  // Disable disables all interrupts and returns the previous interrupt state. It
    11  // can be used in a critical section like this:
    12  //
    13  //	state := interrupt.Disable()
    14  //	// critical section
    15  //	interrupt.Restore(state)
    16  //
    17  // Critical sections can be nested. Make sure to call Restore in the same order
    18  // as you called Disable (this happens naturally with the pattern above).
    19  func Disable() (state State) {
    20  	// SREG is at I/O address 0x3f.
    21  	return State(device.AsmFull(`
    22  		in {}, 0x3f
    23  		cli
    24  	`, nil))
    25  }
    26  
    27  // Restore restores interrupts to what they were before. Give the previous state
    28  // returned by Disable as a parameter. If interrupts were disabled before
    29  // calling Disable, this will not re-enable interrupts, allowing for nested
    30  // cricital sections.
    31  func Restore(state State) {
    32  	// SREG is at I/O address 0x3f.
    33  	device.AsmFull("out 0x3f, {state}", map[string]interface{}{
    34  		"state": state,
    35  	})
    36  }
    37  
    38  // In returns whether the system is currently in an interrupt.
    39  //
    40  // Warning: this always returns false on AVR, as there does not appear to be a
    41  // reliable way to determine whether we're currently running inside an interrupt
    42  // handler.
    43  func In() bool {
    44  	return false
    45  }