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authorJoel Sherrill <joel.sherrill@OARcorp.com>1999-02-18 20:58:46 +0000
committerJoel Sherrill <joel.sherrill@OARcorp.com>1999-02-18 20:58:46 +0000
commit3204a06ba5d7d3be79df589e3230bfa6df386336 (patch)
tree7cf3ce60f8709e553fa14c5e58c7053a4abfac6b /c/src/lib/libbsp
parentAdded NE2000 Driver from Ian Lance Taylor <ian@airs.com>. Comments: (diff)
downloadrtems-3204a06ba5d7d3be79df589e3230bfa6df386336.tar.bz2
Added comments.
Diffstat (limited to 'c/src/lib/libbsp')
-rw-r--r--c/src/lib/libbsp/i386/pc386/ne2000/ne2000.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/i386/pc386/ne2000/ne2000.c b/c/src/lib/libbsp/i386/pc386/ne2000/ne2000.c
index 8493c2829b..7684995309 100644
--- a/c/src/lib/libbsp/i386/pc386/ne2000/ne2000.c
+++ b/c/src/lib/libbsp/i386/pc386/ne2000/ne2000.c
@@ -7,6 +7,26 @@
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
+ *
+ * Both the ne2000 and the wd80x3 are based on the National Semiconductor
+ * 8390 chip, so there is a fair amount of overlap between the two
+ * drivers. It would be possible in principle to combine some code into
+ * a separate set of subroutines called by both. In fact, the drivers in
+ * both OpenBSD and Linux work this way. I didn't bother, because for
+ * the relatively simple drivers used by RTEMS, the overlap is not
+ * especially large, and any reasonable use of subroutines would lead to
+ * slightly less efficient code.
+
+ * This ne2000 driver uses two transmit buffers. While one packet is
+ * being transmitted over the Ethernet, RTEMS will upload another. Since
+ * uploading a packet to the ne2000 is rather slow, I don't think there
+ * is any point to having more than two transmit buffers. However, the
+ * code does make it possible, by changing NE_TX_BUFS, although that
+ * would of course reduce the number of receive buffers.
+ *
+ * I suspect that the wd80x3 driver would benefit slightly from copying
+ * the multiple transmit buffer code. However, I have no way to test
+ * that.
*/
#include <bsp.h>