X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdevices%2Fserial.c;h=099b22841efeafd4289f718210ffb592f8148f57;hb=ac128198b7500ae73aaceba3bd2096add2960b20;hp=1d0607ba0006b91f3d93770136d596bb3e969e59;hpb=605dc396d6dc9f2111e1c1938daa51e3f3bc75c3;p=pintos-anon

diff --git a/src/devices/serial.c b/src/devices/serial.c
index 1d0607b..099b228 100644
--- a/src/devices/serial.c
+++ b/src/devices/serial.c
@@ -9,7 +9,9 @@
 
 /* Register definitions for the 16550A UART used in PCs.
    The 16550A has a lot more going on than shown here, but this
-   is all we need. */
+   is all we need.
+
+   Refer to [PC16650D] for hardware information. */
 
 /* I/O port base address for the first serial port. */
 #define IO_BASE 0x3f8
@@ -129,6 +131,8 @@ set_serial (int bps)
   int baud_base = 1843200 / 16;         /* Base rate of 16550A. */
   uint16_t divisor = baud_base / bps;   /* Clock rate divisor. */
 
+  ASSERT (bps >= 300 && bps <= 115200);
+
   /* Enable DLAB. */
   outb (LCR_REG, LCR_N81 | LCR_DLAB);