mirror of https://gitee.com/openkylin/linux.git
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>
This commit is contained in:
Denys Vlasenko
Thomas Gleixner
parent
b6fbb669c8
commit
9b706aee7d
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@ -33,8 +33,8 @@ static int skip_atoi(const char **s)
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#define PLUS 4 /* show plus */
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#define SPACE 8 /* space if plus */
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#define LEFT 16 /* left justified */
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#define SPECIAL 32 /* 0x */
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#define LARGE 64 /* use 'ABCDEF' instead of 'abcdef' */
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#define SMALL 32 /* Must be 32 == 0x20 */
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#define SPECIAL 64 /* 0x */
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#define do_div(n,base) ({ \
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int __res; \
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@ -45,12 +45,16 @@ __res; })
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static char *number(char *str, long num, int base, int size, int precision,
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int type)
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{
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char c, sign, tmp[66];
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const char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
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/* we are called with base 8, 10 or 16, only, thus don't need "G..." */
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static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
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char tmp[66];
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char c, sign, locase;
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int i;
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if (type & LARGE)
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digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
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/* locase = 0 or 0x20. ORing digits or letters with 'locase'
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* produces same digits or (maybe lowercased) letters */
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locase = (type & SMALL);
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if (type & LEFT)
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type &= ~ZEROPAD;
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if (base < 2 || base > 36)
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@ -81,7 +85,7 @@ static char *number(char *str, long num, int base, int size, int precision,
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tmp[i++] = '0';
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else
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while (num != 0)
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tmp[i++] = digits[do_div(num, base)];
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tmp[i++] = (digits[do_div(num, base)] | locase);
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if (i > precision)
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precision = i;
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size -= precision;
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@ -95,7 +99,7 @@ static char *number(char *str, long num, int base, int size, int precision,
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*str++ = '0';
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else if (base == 16) {
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*str++ = '0';
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*str++ = digits[33];
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*str++ = ('X' | locase);
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}
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}
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if (!(type & LEFT))
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@ -244,9 +248,9 @@ int vsprintf(char *buf, const char *fmt, va_list args)
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base = 8;
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break;
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case 'X':
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flags |= LARGE;
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case 'x':
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flags |= SMALL;
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case 'X':
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base = 16;
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break;
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@ -26,6 +26,9 @@
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#include <asm/page.h> /* for PAGE_SIZE */
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#include <asm/div64.h>
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/* Works only for digits and letters, but small and fast */
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#define TOLOWER(x) ((x) | 0x20)
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/**
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* simple_strtoul - convert a string to an unsigned long
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* @cp: The start of the string
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@ -41,17 +44,17 @@ unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
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if (*cp == '0') {
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base = 8;
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cp++;
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if ((toupper(*cp) == 'X') && isxdigit(cp[1])) {
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if ((TOLOWER(*cp) == 'x') && isxdigit(cp[1])) {
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cp++;
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base = 16;
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}
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}
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} else if (base == 16) {
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if (cp[0] == '0' && toupper(cp[1]) == 'X')
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if (cp[0] == '0' && TOLOWER(cp[1]) == 'x')
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cp += 2;
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}
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while (isxdigit(*cp) &&
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(value = isdigit(*cp) ? *cp-'0' : toupper(*cp)-'A'+10) < base) {
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(value = isdigit(*cp) ? *cp-'0' : TOLOWER(*cp)-'a'+10) < base) {
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result = result*base + value;
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cp++;
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}
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@ -92,17 +95,17 @@ unsigned long long simple_strtoull(const char *cp,char **endp,unsigned int base)
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if (*cp == '0') {
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base = 8;
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cp++;
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if ((toupper(*cp) == 'X') && isxdigit(cp[1])) {
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if ((TOLOWER(*cp) == 'x') && isxdigit(cp[1])) {
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cp++;
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base = 16;
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}
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}
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} else if (base == 16) {
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if (cp[0] == '0' && toupper(cp[1]) == 'X')
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if (cp[0] == '0' && TOLOWER(cp[1]) == 'x')
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cp += 2;
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}
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while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : (islower(*cp)
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? toupper(*cp) : *cp)-'A'+10) < base) {
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while (isxdigit(*cp)
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&& (value = isdigit(*cp) ? *cp-'0' : TOLOWER(*cp)-'a'+10) < base) {
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result = result*base + value;
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cp++;
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}
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@ -360,24 +363,25 @@ static noinline char* put_dec(char *buf, unsigned long long num)
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#define PLUS 4 /* show plus */
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#define SPACE 8 /* space if plus */
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#define LEFT 16 /* left justified */
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#define SPECIAL 32 /* 0x */
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#define LARGE 64 /* use 'ABCDEF' instead of 'abcdef' */
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#define SMALL 32 /* Must be 32 == 0x20 */
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#define SPECIAL 64 /* 0x */
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static char *number(char *buf, char *end, unsigned long long num, int base, int size, int precision, int type)
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{
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char sign,tmp[66];
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const char *digits;
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/* we are called with base 8, 10 or 16, only, thus don't need "g..." */
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static const char small_digits[] = "0123456789abcdefx"; /* "ghijklmnopqrstuvwxyz"; */
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static const char large_digits[] = "0123456789ABCDEFX"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
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/* we are called with base 8, 10 or 16, only, thus don't need "G..." */
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static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
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char tmp[66];
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char sign;
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char locase;
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int need_pfx = ((type & SPECIAL) && base != 10);
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int i;
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digits = (type & LARGE) ? large_digits : small_digits;
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/* locase = 0 or 0x20. ORing digits or letters with 'locase'
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* produces same digits or (maybe lowercased) letters */
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locase = (type & SMALL);
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if (type & LEFT)
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type &= ~ZEROPAD;
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if (base < 2 || base > 36)
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return NULL;
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sign = 0;
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if (type & SIGN) {
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if ((signed long long) num < 0) {
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@ -404,7 +408,7 @@ static char *number(char *buf, char *end, unsigned long long num, int base, int
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tmp[i++] = '0';
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/* Generic code, for any base:
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else do {
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tmp[i++] = digits[do_div(num,base)];
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tmp[i++] = (digits[do_div(num,base)] | locase);
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} while (num != 0);
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*/
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else if (base != 10) { /* 8 or 16 */
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@ -412,7 +416,7 @@ static char *number(char *buf, char *end, unsigned long long num, int base, int
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int shift = 3;
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if (base == 16) shift = 4;
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do {
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tmp[i++] = digits[((unsigned char)num) & mask];
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tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
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num >>= shift;
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} while (num);
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} else { /* base 10 */
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@ -444,7 +448,7 @@ static char *number(char *buf, char *end, unsigned long long num, int base, int
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++buf;
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if (base == 16) {
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if (buf < end)
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*buf = digits[16]; /* for arbitrary base: digits[33]; */
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*buf = ('X' | locase);
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++buf;
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}
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}
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@ -644,6 +648,7 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
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continue;
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case 'p':
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flags |= SMALL;
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if (field_width == -1) {
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field_width = 2*sizeof(void *);
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flags |= ZEROPAD;
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@ -680,9 +685,9 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
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base = 8;
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break;
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case 'X':
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flags |= LARGE;
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case 'x':
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flags |= SMALL;
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case 'X':
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base = 16;
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break;
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