From 3204a06ba5d7d3be79df589e3230bfa6df386336 Mon Sep 17 00:00:00 2001 From: Joel Sherrill Date: Thu, 18 Feb 1999 20:58:46 +0000 Subject: Added comments. --- c/src/lib/libbsp/i386/pc386/ne2000/ne2000.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) 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 -- cgit v1.2.3