Allow other image file names through cli args, increase ram size, update readme

src/main.rs

@@ -5,6 +5,7 @@
 // See LICENSE file in the project root for full license text.
 
 use std::{
+    env,
     error::Error,
     fs::File,
     io::{self, Read},
@@ -41,9 +42,16 @@ fn read_file_to_buffer(path: &str, buffer: &mut [u8]) -> io::Result<usize> {
 }
 
 fn main() -> Result<(), Box<dyn Error>> {
-    let mut ram = Ram::try_new(1024 * 1024 / 4096)?;
+    let mut ram = Ram::try_new(16 * 1024 * 1024 / 4096)?;
     let buf = ram.buf_mut();
-    read_file_to_buffer("./img", buf)?;
+
+    let args: Vec<String> = env::args().collect();
+
+    if args.len() != 2 {
+        eprintln!("USAGE: trve <ram_image>")
+    }
+
+    read_file_to_buffer(&args[1], buf)?;
 
     let uart = BasicUart::new();
     let uart = uart.spawn_poller(Duration::from_millis(10));