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(__strtol_ul_max_tab, __strtol_ull_max_tab, __strtol_ull_rem_tab, __strtol_ul_rem_tab, cutoff_tab, cutlim_tab, jmax_tab): New. (__strtol_l): Use them to avoid runtime division.

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This commit is contained in:
Ulrich Drepper 2004-03-25 22:58:59 +00:00
parent db2f05ba83
commit af15df12ee
1 changed files with 47 additions and 3 deletions
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50
sysdeps/generic/strtol_l.c
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@ -44,6 +44,7 @@
#include <string.h>
#include <locale.h>
#include <xlocale.h>
#include <bits/wordsize.h>
#ifdef USE_NUMBER_GROUPING
# include "../locale/localeinfo.h"
@ -164,6 +165,48 @@
#endif
/* Define tables of maximum values and remainders in order to detect
overflow. Do this at compile-time in order to avoid the runtime
overhead of the division. */
#define DEF(TYPE, NAME) \
const TYPE NAME[] attribute_hidden \
__attribute__((section(".gnu.linkonce.ro." #NAME))) = \
{ \
F(2), F(3), F(4), F(5), F(6), F(7), F(8), F(9), F(10), \
F(11), F(12), F(13), F(14), F(15), F(16), F(17), F(18), F(19), F(20), \
F(21), F(22), F(23), F(24), F(25), F(26), F(27), F(28), F(29), F(30), \
F(31), F(32), F(33), F(34), F(35), F(36) \
}
#define F(X) ULONG_MAX / X
DEF (unsigned long, __strtol_ul_max_tab);
#undef F
#if defined(QUAD) && __WORDSIZE == 32
# define F(X) ULONG_LONG_MAX / X
DEF (unsigned long long, __strtol_ull_max_tab);
# undef F
# define F(X) ULONG_LONG_MAX % X
DEF (unsigned char, __strtol_ull_rem_tab);
# undef F
#else
# define F(X) ULONG_MAX % X
DEF (unsigned char, __strtol_ul_rem_tab);
# undef F
#endif
#undef DEF
/* Define some more readable aliases for these arrays which correspond
to how they'll be used in the function below. */
#define jmax_tab __strtol_ul_max_tab
#if defined(QUAD) && __WORDSIZE == 32
# define cutoff_tab __strtol_ull_max_tab
# define cutlim_tab __strtol_ull_rem_tab
#else
# define cutoff_tab __strtol_ul_max_tab
# define cutlim_tab __strtol_ul_rem_tab
#endif
/* Convert NPTR to an `unsigned long int' or `long int' in base BASE.
If BASE is 0 the base is determined by the presence of a leading
@ -325,8 +368,9 @@ INTERNAL (__strtol_l) (nptr, endptr, base, group, loc)
#endif
end = NULL;
cutoff = STRTOL_ULONG_MAX / (unsigned LONG int) base;
cutlim = STRTOL_ULONG_MAX % (unsigned LONG int) base;
/* Avoid runtime division; lookup cutoff and limit. */
cutoff = cutoff_tab[base - 2];
cutlim = cutlim_tab[base - 2];
overflow = 0;
i = 0;
@ -334,7 +378,7 @@ INTERNAL (__strtol_l) (nptr, endptr, base, group, loc)
if (sizeof (long int) != sizeof (LONG int))
{
unsigned long int j = 0;
unsigned long int jmax = ULONG_MAX / base;
unsigned long int jmax = jmax_tab[base - 2];
for (;c != L_('\0'); c = *++s)
{