start implementation of a StaticAllocator

master
Astro 3 years ago
parent fc39885d3b
commit 7cdf6c0918
  1. 1
      src/main.rs
  2. 75
      src/ram.rs

@ -20,6 +20,7 @@ mod regs;
mod cortex_a9;
mod stdio;
mod zynq;
mod ram;
use crate::regs::{RegisterR, RegisterW};
use crate::cortex_a9::{asm, regs::*, mmu};

@ -0,0 +1,75 @@
use core::mem::{align_of, size_of};
pub trait RAM {
#[inline(always)]
fn addr(&self) -> usize;
#[inline(always)]
fn size(&self) -> usize;
#[inline(always)]
fn into_memory_region(&self) -> MemoryRegion {
MemoryRegion {
addr: self.addr(),
size: self.size(),
}
}
}
pub struct MemoryRegion {
addr: usize,
size: usize,
}
impl MemoryRegion {
#[inline(always)]
fn split(&mut self, offset: usize) -> MemoryRegion {
if offset > self.size {
panic!("StaticAllocator: unable to split {}/{} bytes", offset, self.size);
}
let result = MemoryRegion {
addr: self.addr,
size: offset,
};
self.addr += offset;
self.size -= offset;
result
}
unsafe fn clear<T>(self) -> *mut T {
let result = self.addr as *mut T;
for b in core::slice::from_raw_parts_mut::<u8>(result as *mut u8, self.size) {
*b = 0;
}
result
}
pub fn align(&mut self, alignment: usize) {
let mask = alignment - 1;
let addr = (self.addr | mask) + 1;
self.size -= addr - self.addr;
self.addr = addr;
}
}
pub struct StaticAllocator {
free: MemoryRegion,
}
impl StaticAllocator {
pub fn new<R: RAM>(r: R) -> Self {
StaticAllocator {
free: r.into_memory_region(),
}
}
pub fn alloc<'a: 'b, 'b, T: Sized>(&'a mut self) -> &'b mut T {
self.free.align(align_of::<T>());
let size = size_of::<T>();
let region = self.free.split(size);
unsafe { &mut *region.clear() }
}
}
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