emcell 0.0.4

Reserve flash memory regions to safely keep multiple binary and library binaries (cells) on a microcontroller. The cells can call functions from other cells.
Documentation 
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/// Must be called once to initialize memory
/// It is enforced by rule "only one forward extern for cell"
pub unsafe fn init() {
    init_memory();
}

use core::ptr::{addr_of, addr_of_mut};

/// Initialize BSS and DATA sections
/// Should not be called directly! Header wrapper use this function to initialize memory on first cell access
#[inline(always)]
#[cfg(feature = "rt-crate-cortex-m-rt")]
pub unsafe fn init_memory() {
    use core::ptr;

    extern "C" {
        static mut __sbss: u32;
        static mut __ebss: u32;

        static mut __sdata: u32;
        static mut __edata: u32;
        static mut __sidata: u32;
    }
    let count = addr_of!(__ebss) as usize - addr_of!(__sbss) as usize;
    let addr = addr_of_mut!(__sbss) as *mut u8;
    if count > 0 {
        ptr::write_bytes(addr, 0, count);
    }

    let count = addr_of!(__edata) as usize - addr_of!(__sdata) as usize;
    if count > 0 {
        ptr::copy_nonoverlapping(
            addr_of!(__sidata) as *const u8,
            addr_of_mut!(__sdata) as *mut u8,
            count);
    }
}

#[cfg(feature = "rt-crate-cortex-m-rt")]
pub unsafe fn switch_vectors() {
    extern "C" {
        static mut __vector_table: u32;
    }
    let vector_table = addr_of_mut!(__vector_table) as *mut u32;

    let scb = unsafe {&*cortex_m::peripheral::SCB::PTR};

    // let vtor = scb.vtor.read() as *mut u32;
    scb.vtor.write(vector_table as u32);
}