implement a simple uart + show that kernel test works

1 files changed, 12 insertions, 4 deletions

diff --git a/src/main.rs b/src/main.rs
index bbf89b6..a3571c7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,14 +5,11 @@ pub mod state;
 use crate::core::*;
 use crate::mem::Memory;
 use crate::state::CpuState;
-use std::collections::HashSet;
-use std::io;
-use std::io::Write;
-use std::process::exit;
 
 const MEMORY_SIZE: usize = 64 * 1024 * 1024;
 const REGISTER_NAME_WIDTH: u32 = 0b11111;
 const RO_TARGET: u32 = 0x80000000;
+const UART_ADDR: u32 = 0x10000000;
 
 fn main() {
     let path = std::path::PathBuf::from("wkern.bin");
@@ -22,9 +19,20 @@ fn main() {
 
     let mut state = CpuState::new(memory);
 
+    state.memory.write_multiple_bytes(RO_TARGET as usize, f_dat.as_slice(), 99).unwrap();
+    state.memory.write(UART_ADDR as usize, 99, 0).unwrap();
+    state.pc = RO_TARGET;
+
     loop {
         {
             handle_instruction(&mut state);
+
+            // simple polling uart
+            let uart_byte = state.memory.read(UART_ADDR as usize, 99).unwrap();
+            if uart_byte != 0 {
+                print!("{}", uart_byte as char);
+            }
+            state.memory.write(UART_ADDR as usize, 99, 0).unwrap();
         }
     }
 }