ensure FIFO has space before transmit

Signed-off-by: Josh Felmeden <[email protected]>
seL4 · Jan 19, 2024 · 0900305 · 0900305
1 parent 785263f
commit 0900305
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/loader/src/loader.c b/loader/src/loader.c
@@ -152,9 +152,14 @@ putc(uint8_t ch)
 static void
 putc(uint8_t ch)
 {
-    while (!(*UART_REG(STAT) & STAT_TDRE)) { }
-    if (ch == '\n')
+    if (ch == '\n') {
+        // ensure FIFO has space
+        while (!(*UART_REG(STAT) & STAT_TDRE)) { }
         *UART_REG(TRANSMIT) = '\r';
+    }     
+
+    // ensure FIFO has space
+    while (!(*UART_REG(STAT) & STAT_TDRE)) { }
     *UART_REG(TRANSMIT) = ch;
 }
 #else