console/uart tweaks

1 files changed, 13 insertions, 6 deletions

diff --git a/kernel/console.c b/kernel/console.c
index 650e2af..6fb79cd 100644
--- a/kernel/console.c
+++ b/kernel/console.c
@@ -39,7 +39,7 @@ consputc(int c)
   }
 
   if(c == BACKSPACE){
-    // if the user typed backspace, erase the character.
+    // if the user typed backspace, overwrite with a space.
     uartputc('\b'); uartputc(' '); uartputc('\b');
   } else {
     uartputc(c);
@@ -134,10 +134,10 @@ consoleread(int user_dst, uint64 dst, int n)
 }
 
 //
-// the uart interrupt handler, uartintr(), calls this
-// for each input character. do erase/kill processing,
-// append to cons.buf, wake up reader if a whole
-// line has arrived.
+// the console input interrupt handler.
+// uartintr() calls this for input character.
+// do erase/kill processing, append to cons.buf,
+// wake up consoleread() if a whole line has arrived.
 //
 void
 consoleintr(int c)
@@ -165,9 +165,16 @@ consoleintr(int c)
   default:
     if(c != 0 && cons.e-cons.r < INPUT_BUF){
       c = (c == '\r') ? '\n' : c;
-      cons.buf[cons.e++ % INPUT_BUF] = c;
+
+      // echo back to the user.
       consputc(c);
+
+      // store for consumption by consoleread().
+      cons.buf[cons.e++ % INPUT_BUF] = c;
+
       if(c == '\n' || c == C('D') || cons.e == cons.r+INPUT_BUF){
+        // wake up consoleread() if a whole line (or end-of-file)
+        // has arrived.
         cons.w = cons.e;
         wakeup(&cons.r);
       }