[src/trunk]: src/sys/dev/pci/voyager add fastpaths for alpha == 0 and alpha =...

[macallan <macallan%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b66e43551094
branches:  trunk
changeset: 772269:b66e43551094
user:      macallan <macallan%NetBSD.org@localhost>
date:      Tue Dec 27 07:05:53 2011 +0000

description:
add fastpaths for alpha == 0 and alpha == 255 - no need to do the six
multiplications dance there, just use background or foreground colour

diffstat:

 sys/dev/pci/voyager/voyagerfb.c |  22 ++++++++++++++--------
 1 files changed, 14 insertions(+), 8 deletions(-)

diffs (43 lines):

diff -r 756026a1f583 -r b66e43551094 sys/dev/pci/voyager/voyagerfb.c
--- a/sys/dev/pci/voyager/voyagerfb.c   Tue Dec 27 06:24:40 2011 +0000
+++ b/sys/dev/pci/voyager/voyagerfb.c   Tue Dec 27 07:05:53 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: voyagerfb.c,v 1.13 2011/12/24 02:28:50 macallan Exp $  */
+/*     $NetBSD: voyagerfb.c,v 1.14 2011/12/27 07:05:53 macallan Exp $  */
 
 /*
  * Copyright (c) 2009, 2011 Michael Lorenz
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: voyagerfb.c,v 1.13 2011/12/24 02:28:50 macallan Exp $");
+__KERNEL_RCSID(0, "$NetBSD: voyagerfb.c,v 1.14 2011/12/27 07:05:53 macallan Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -923,12 +923,18 @@
                        for (i = 0; i < wi * he; i++) {
                                aval = *data;
                                data++;
-                               r = aval * rf + (255 - aval) * rb;
-                               g = aval * gf + (255 - aval) * gb;
-                               b = aval * bf + (255 - aval) * bb;
-                               pixel = (r & 0xff00) << 8 |
-                                       (g & 0xff00) |
-                                       (b & 0xff00) >> 8;
+                               if (aval == 0) {
+                                       pixel = bg;
+                               } else if (aval == 255) {
+                                       pixel = fg;
+                               } else {
+                                       r = aval * rf + (255 - aval) * rb;
+                                       g = aval * gf + (255 - aval) * gb;
+                                       b = aval * bf + (255 - aval) * bb;
+                                       pixel = (r & 0xff00) << 8 |
+                                               (g & 0xff00) |
+                                               (b & 0xff00) >> 8;
+                               }
                                bus_space_write_4(sc->sc_memt, sc->sc_regh,
                                    SM502_DATAPORT, pixel);
                        }