interrupt-driven uart output, hopefully a nice example for teaching.

1 files changed, 5 insertions, 3 deletions

diff --git a/kernel/console.c b/kernel/console.c
index 87a83ff..a97ef30 100644
--- a/kernel/console.c
+++ b/kernel/console.c
@@ -27,6 +27,8 @@
 
 //
 // send one character to the uart.
+// called by printf, and to echo input characters,
+// but not from write().
 //
 void
 consputc(int c)
@@ -40,9 +42,9 @@ consputc(int c)
 
   if(c == BACKSPACE){
     // if the user typed backspace, overwrite with a space.
-    uartputc('\b'); uartputc(' '); uartputc('\b');
+    uartputc('\b', 0); uartputc(' ', 0); uartputc('\b', 0);
   } else {
-    uartputc(c);
+    uartputc(c, 0);
   }
 }
 
@@ -70,7 +72,7 @@ consolewrite(int user_src, uint64 src, int n)
     char c;
     if(either_copyin(&c, user_src, src+i, 1) == -1)
       break;
-    consputc(c);
+    uartputc(c, 1);
   }
   release(&cons.lock);