diff options
| author | Denys Vlasenko <vda.linux@googlemail.com> | 2008-02-09 23:24:09 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2008-02-09 23:24:09 +0100 |
| commit | 9b706aee7d92d6ac3002547aea12e3eaa0a750ae (patch) | |
| tree | b1e945b7d6eccd4ef44d80e1f3a4596a4a629c78 /arch/x86/boot/printf.c | |
| parent | b6fbb669c8ef3a112121697ca901c290ccd35eb2 (diff) | |
| download | linux-9b706aee7d92d6ac3002547aea12e3eaa0a750ae.tar.bz2 | |
x86: trivial printk optimizations
In arch/x86/boot/printf.c gets rid of unused tail of digits: const char
*digits = "0123456789abcdefghijklmnopqrstuvwxyz"; (we are using 0-9a-f
only)
Uses smaller/faster lowercasing (by ORing with 0x20)
if we know that we work on numbers/digits. Makes
strtoul smaller, and also we are getting rid of
static const char small_digits[] = "0123456789abcdefx";
static const char large_digits[] = "0123456789ABCDEFX";
since this works equally well:
static const char digits[16] = "0123456789ABCDEF";
Size savings:
$ size vmlinux.org vmlinux
text data bss dec hex filename
877320 112252 90112 1079684 107984 vmlinux.org
877048 112252 90112 1079412 107874 vmlinux
It may be also a tiny bit faster because code has less
branches now, but I doubt it is measurable.
[ hugh@veritas.com: uppercase pointers fix ]
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/boot/printf.c')
| -rw-r--r-- | arch/x86/boot/printf.c | 24 |
1 files changed, 14 insertions, 10 deletions
diff --git a/arch/x86/boot/printf.c b/arch/x86/boot/printf.c index 1a09f9309d3c..7e7e890699be 100644 --- a/arch/x86/boot/printf.c +++ b/arch/x86/boot/printf.c @@ -33,8 +33,8 @@ static int skip_atoi(const char **s) #define PLUS 4 /* show plus */ #define SPACE 8 /* space if plus */ #define LEFT 16 /* left justified */ -#define SPECIAL 32 /* 0x */ -#define LARGE 64 /* use 'ABCDEF' instead of 'abcdef' */ +#define SMALL 32 /* Must be 32 == 0x20 */ +#define SPECIAL 64 /* 0x */ #define do_div(n,base) ({ \ int __res; \ @@ -45,12 +45,16 @@ __res; }) static char *number(char *str, long num, int base, int size, int precision, int type) { - char c, sign, tmp[66]; - const char *digits = "0123456789abcdefghijklmnopqrstuvwxyz"; + /* we are called with base 8, 10 or 16, only, thus don't need "G..." */ + static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */ + + char tmp[66]; + char c, sign, locase; int i; - if (type & LARGE) - digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; + /* locase = 0 or 0x20. ORing digits or letters with 'locase' + * produces same digits or (maybe lowercased) letters */ + locase = (type & SMALL); if (type & LEFT) type &= ~ZEROPAD; if (base < 2 || base > 36) @@ -81,7 +85,7 @@ static char *number(char *str, long num, int base, int size, int precision, tmp[i++] = '0'; else while (num != 0) - tmp[i++] = digits[do_div(num, base)]; + tmp[i++] = (digits[do_div(num, base)] | locase); if (i > precision) precision = i; size -= precision; @@ -95,7 +99,7 @@ static char *number(char *str, long num, int base, int size, int precision, *str++ = '0'; else if (base == 16) { *str++ = '0'; - *str++ = digits[33]; + *str++ = ('X' | locase); } } if (!(type & LEFT)) @@ -244,9 +248,9 @@ int vsprintf(char *buf, const char *fmt, va_list args) base = 8; break; - case 'X': - flags |= LARGE; case 'x': + flags |= SMALL; + case 'X': base = 16; break; |