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use crate::util::constants::LOG_BYTES_IN_PAGE;
use crate::util::Address;

/* The (log of the) size of each region of meta data management */
pub const LOG_BYTES_IN_REGION: usize = 22;
pub const BYTES_IN_REGION: usize = 1 << LOG_BYTES_IN_REGION;
pub const REGION_MASK: usize = BYTES_IN_REGION - 1;
pub const LOG_PAGES_IN_REGION: usize = LOG_BYTES_IN_REGION - LOG_BYTES_IN_PAGE as usize;
pub const PAGES_IN_REGION: usize = 1 << LOG_PAGES_IN_REGION;

pub fn get_metadata_base(address: Address) -> Address {
    address.align_down(BYTES_IN_REGION)
}

pub fn get_metadata_offset(address: Address, log_coverage: usize, log_align: usize) -> usize {
    ((address & REGION_MASK) >> (log_coverage + log_align)) << log_align
}