summaryLevelBits,
	summaryLevelBits,
	summaryLevelBits,
}

// levelShift is the number of bits to shift to acquire the radix for a given level
// in the super summary structure.
//
// With levelShift, one can compute the index of the summary at level l related to a
// pointer p by doing:
//
//	p >> levelShift[l]
var levelShift = [summaryLevels]uint{
	heapAddrBits - summaryL0Bits,

)

// See comment in mpagealloc_64bit.go.
var levelBits = [summaryLevels]uint{
	summaryL0Bits,
	summaryLevelBits,
	summaryLevelBits,
	summaryLevelBits,
}

// See comment in mpagealloc_64bit.go.
var levelShift = [summaryLevels]uint{
	heapAddrBits - summaryL0Bits,
	heapAddrBits - summaryL0Bits - 1*summaryLevelBits,
	heapAddrBits - summaryL0Bits - 2*summaryLevelBits,
	heapAddrBits - summaryL0Bits - 3*summaryLevelBits,
}

func offAddrToLevelIndex(level int, addr offAddr) int {
	return int((addr.a - arenaBaseOffset) >> levelShift[level])
}

// levelIndexToOffAddr converts an index into summary[level] into
// the corresponding address in the offset address space.
func levelIndexToOffAddr(level, idx int) offAddr {
	return offAddr{(uintptr(idx) << levelShift[level]) + arenaBaseOffset}
}

// addrsToSummaryRange converts base and limit pointers into a range