File size: 1,840 Bytes
1d3f990 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 | //! Memory Model — Von Neumann unified address space
use anyhow::{Result, anyhow};
use std::fmt;
pub type Address = usize;
pub type Word = i64;
/// Flat 64-bit memory model with code and data unified
#[derive(Clone)]
pub struct Memory {
cells: Vec<Word>,
max_addr: Address,
}
impl Memory {
pub fn new(size: Address) -> Self {
Self {
cells: vec![0; size],
max_addr: size - 1,
}
}
pub fn read(&self, addr: Address) -> Option<Word> {
if addr <= self.max_addr {
Some(self.cells[addr])
} else {
None
}
}
pub fn write(&mut self, addr: Address, value: Word) -> Result<()> {
if addr > self.max_addr {
return Err(anyhow!("Address out of bounds: {} (max {})", addr, self.max_addr));
}
self.cells[addr] = value;
Ok(())
}
pub fn size(&self) -> Address {
self.cells.len()
}
pub fn as_slice(&self) -> &[Word] {
&self.cells
}
pub fn as_mut_slice(&mut self) -> &mut [Word] {
&mut self.cells
}
}
impl fmt::Debug for Memory {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Memory")
.field("size", &self.cells.len())
.field("sample", &self.cells.iter().take(10).collect::<Vec<_>>())
.finish()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_memory_basic() {
let mut mem = Memory::new(1024);
mem.write(0, 42).unwrap();
assert_eq!(mem.read(0), Some(42));
}
#[test]
fn test_memory_bounds() {
let mem = Memory::new(10);
assert_eq!(mem.read(5), Some(0));
assert_eq!(mem.read(15), None);
}
}
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