util/nvmutil: optimise cmd_swap() further

don't do xor swap. we know gbe2 is always 4KB higher than
gbe in memory, so we can just set gbe2 to the value of gbe,
and OR the size in bytes of 4KB into gbe2

this is only a marginal speed boost, negligible even, but it's
done for the lulz

1 files changed, 5 insertions, 7 deletions

diff --git a/util/nvmutil/nvmutil.c b/util/nvmutil/nvmutil.c
index 9a70634..7627355 100644
--- a/util/nvmutil/nvmutil.c
+++ b/util/nvmutil/nvmutil.c
@@ -355,18 +355,16 @@ void
 cmd_swap(void)
 {
 	int part0, part1;
-	size_t g1 = (size_t) gbe;
-	size_t g2 = (size_t) gbe2;
+	size_t ptr;
 
 	part0 = validChecksum(0);
 	part1 = validChecksum(1);
 
 	if (part0 || part1) {
-		g1 ^= g2;
-		g2 ^= g1;
-		g1 ^= g2;
-		gbe = (uint8_t *) g1;
-		gbe2 = (uint8_t *) g2;
+		gbe2 = gbe;
+		ptr = (size_t) gbe;
+		ptr |= SIZE_4KB;
+		gbe = (uint8_t *) ptr;
 
 		gbeFileModified = 1;
 		nvmPartModified[0] = 1;