// +build cortexm

package interrupt

import (
	"device/arm"
)

// Enable enables this interrupt. Right after calling this function, the
// interrupt may be invoked if it was already pending.
func (irq Interrupt) Enable() {
	arm.EnableIRQ(uint32(irq.num))
}

// Disable disables this interrupt.
func (irq Interrupt) Disable() {
	arm.DisableIRQ(uint32(irq.num))
}

// SetPriority sets the interrupt priority for this interrupt. A lower number
// means a higher priority. Additionally, most hardware doesn't implement all
// priority bits (only the uppoer bits).
//
// Examples: 0xff (lowest priority), 0xc0 (low priority), 0x00 (highest possible
// priority).
func (irq Interrupt) SetPriority(priority uint8) {
	arm.SetPriority(uint32(irq.num), uint32(priority))
}

// State represents the previous global interrupt state.
type State uintptr

// Disable disables all interrupts and returns the previous interrupt state. It
// can be used in a critical section like this:
//
//     state := interrupt.Disable()
//     // critical section
//     interrupt.Restore(state)
//
// Critical sections can be nested. Make sure to call Restore in the same order
// as you called Disable (this happens naturally with the pattern above).
func Disable() (state State) {
	return State(arm.DisableInterrupts())
}

// Restore restores interrupts to what they were before. Give the previous state
// returned by Disable as a parameter. If interrupts were disabled before
// calling Disable, this will not re-enable interrupts, allowing for nested
// cricital sections.
func Restore(state State) {
	arm.EnableInterrupts(uintptr(state))
}
