Function accessible_pages 

pub fn accessible_pages(mem_size: u32, data_base: u32) -> u32

Accessible 4 KiB page count for an Instance whose data extent is [data_base, mem_size) — the #2 footprint. mem_size is the high-water-mark over the Image’s memory_mappings (javm_cap::image::ImageCap::data_overlays — the single source of truth both engines derive from), so the two engines compute an identical page count. data_base is javm_cap::layout::DATA_BASE (passed in — this crate has no javm-cap dependency).