[U-Boot] [PATCH] Avoid use of divides in print_size.

[Nick Thompson]

Modification of print_size to avoid use of divides and especially
long long divides. Keep the binary scale factor in terms of bit
shifts instead. This should be faster, since the previous code
gave the compiler no clues that the divides where always powers
of two, preventing optimisation.

Signed-off-by: Nick Thompson <nick.thompson at ge.com>
---
This patch should make print_size a little faster, but perhaps
nobody cares about that too much. What it also does though is
reenable U-Boot linking for ARM with standard toolchains.
(e.g. CodeSourcery and MontaVista).

 lib/display_options.c |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/display_options.c b/lib/display_options.c
index 86df05d..636916d 100644
--- a/lib/display_options.c
+++ b/lib/display_options.c
@@ -46,13 +46,14 @@ int display_options (void)
 void print_size(unsigned long long size, const char *s)
 {
 	unsigned long m = 0, n;
+	unsigned long long f;
 	static const char names[] = {'E', 'P', 'T', 'G', 'M', 'K'};
-	unsigned long long d = 1ULL << (10 * ARRAY_SIZE(names));
+	unsigned long d = 10 * ARRAY_SIZE(names);
 	char c = 0;
 	unsigned int i;
 
-	for (i = 0; i < ARRAY_SIZE(names); i++, d >>= 10) {
-		if (size >= d) {
+	for (i = 0; i < ARRAY_SIZE(names); i++, d -= 10) {
+		if (size >> d) {
 			c = names[i];
 			break;
 		}
@@ -63,11 +64,12 @@ void print_size(unsigned long long size, const char *s)
 		return;
 	}
 
-	n = size / d;
+	n = size >> d;
+	f = size & ((1ULL << d) - 1);
 
 	/* If there's a remainder, deal with it */
-	if(size % d) {
-		m = (10 * (size - (n * d)) + (d / 2) ) / d;
+	if (f) {
+		m = (10ULL * (f + (1 << (d - 1)))) >> d;
 
 		if (m >= 10) {
 			m -= 10;
-- 
1.7.0.4