From d8771a27a33b4d3dea017b54cebea37d2801b8b1 Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Fri, 3 Mar 2023 09:36:04 +1100
Subject: [PATCH] ??

---
 src/processor/memory/rom.rs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/processor/memory/rom.rs b/src/processor/memory/rom.rs
index 841bf44..2af2dd1 100644
--- a/src/processor/memory/rom.rs
+++ b/src/processor/memory/rom.rs
@@ -21,7 +21,7 @@ const NUM_WRITES_TO_FLUSH: usize = 256;
 
 impl MaybeBufferedSram {
     fn new(path: Option<PathBuf>, length: usize) -> Self {
-        let mut buf = vec![0; 8 * mbcs::KB];
+        let mut buf = vec![];
         let inner = if let Some(path) = path {
             if path.exists() {
                 let mut writer = OpenOptions::new()
@@ -33,6 +33,7 @@ impl MaybeBufferedSram {
                 writer.read_to_end(&mut buf).unwrap();
                 Some(writer)
             } else {
+                buf.resize(8 * mbcs::KB, 0);
                 let writer = OpenOptions::new()
                     .write(true)
                     .create_new(true)
@@ -66,9 +67,8 @@ impl MaybeBufferedSram {
 
     fn set(&mut self, addr: usize, data: u8) {
         self.unbuffered_writes += 1;
-        if addr >= self.buf.len() {
-            self.buf
-                .resize((addr as f64 / (mbcs::KB as f64 * 8.)).ceil() as usize, 0);
+        while addr >= self.buf.len() {
+            self.buf.resize(self.buf.len() + (8 * mbcs::KB), 0);
         }
         self.buf[addr] = data;
         if self.unbuffered_writes >= NUM_WRITES_TO_FLUSH {
@@ -79,6 +79,7 @@ impl MaybeBufferedSram {
     fn flush(&mut self) {
         if let Some(ref mut writer) = self.inner {
             writer.seek(SeekFrom::Start(0)).unwrap();
+            writer.set_len(self.buf.len() as u64).unwrap();
             writer.write_all(&self.buf).unwrap();
         }
     }