[PATCH 4/4] lib/vsprintf.c: Another small hack

From: Rasmus Villemoes
Date: Fri Feb 20 2015 - 18:22:13 EST


Making ZEROPAD == '0'-' ', we can eliminate a few more instructions.

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
lib/vsprintf.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 7a299d43987a..2753f9261115 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -341,10 +341,10 @@ int num_to_str(char *buf, int size, unsigned long long num)
}

#define SIGN 1 /* unsigned/signed, must be 1 */
-#define ZEROPAD 2 /* pad with zero */
+#define LEFT 2 /* left justified */
#define PLUS 4 /* show plus */
#define SPACE 8 /* space if plus */
-#define LEFT 16 /* left justified */
+#define ZEROPAD 16 /* pad with zero, must be 16 == '0' - ' ' */
#define SMALL 32 /* use lowercase in hex (must be 32 == 0x20) */
#define SPECIAL 64 /* prefix hex with "0x", octal with "0" */

@@ -467,7 +467,8 @@ char *number(char *buf, char *end, unsigned long long num,
}
/* zero or space padding */
if (!(spec.flags & LEFT)) {
- char c = (spec.flags & ZEROPAD) ? '0' : ' ';
+ char c = ' ' + (spec.flags & ZEROPAD);
+ BUILD_BUG_ON(' ' + ZEROPAD != '0');
while (--spec.field_width >= 0) {
if (buf < end)
*buf = c;
--
2.1.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/