Avoid use of divides in print_size

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@ge.com>
Acked-by: Timur Tabi <timur@freescale.com>
This commit is contained in:
Nick Thompson 2010-05-11 11:29:52 +01:00 committed by Wolfgang Denk
parent a599cde769
commit f2d76ae4fd
1 changed files with 8 additions and 6 deletions

View File

@ -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 + (1ULL << (d - 1))) >> d;
if (m >= 10) {
m -= 10;