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efi/printf: Add 64-bit and 8-bit integer support
Support 'll' qualifier for long long by copying the decimal printing code from lib/vsprintf.c. For simplicity, the 32-bit code is used on 64-bit architectures as well. Support 'hh' qualifier for signed/unsigned char type integers. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-8-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Arvind Sankar
Ard Biesheuvel
parent
29a2806653
commit
ce5e3f909f
@ -7,10 +7,7 @@
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* ----------------------------------------------------------------------- */
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/*
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* Oh, it's a waste of space, but oh-so-yummy for debugging. This
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* version of printf() does not include 64-bit support. "Live with
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* it."
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*
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* Oh, it's a waste of space, but oh-so-yummy for debugging.
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*/
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#include <stdarg.h>
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@ -28,6 +25,86 @@ static int skip_atoi(const char **s)
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return i;
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}
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/*
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* put_dec_full4 handles numbers in the range 0 <= r < 10000.
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* The multiplier 0xccd is round(2^15/10), and the approximation
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* r/10 == (r * 0xccd) >> 15 is exact for all r < 16389.
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*/
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static
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void put_dec_full4(char *buf, unsigned int r)
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{
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int i;
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for (i = 0; i < 3; i++) {
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unsigned int q = (r * 0xccd) >> 15;
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*buf++ = '0' + (r - q * 10);
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r = q;
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}
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*buf++ = '0' + r;
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}
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/* put_dec is copied from lib/vsprintf.c with small modifications */
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/*
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* Call put_dec_full4 on x % 10000, return x / 10000.
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* The approximation x/10000 == (x * 0x346DC5D7) >> 43
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* holds for all x < 1,128,869,999. The largest value this
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* helper will ever be asked to convert is 1,125,520,955.
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* (second call in the put_dec code, assuming n is all-ones).
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*/
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static
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unsigned int put_dec_helper4(char *buf, unsigned int x)
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{
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unsigned int q = (x * 0x346DC5D7ULL) >> 43;
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put_dec_full4(buf, x - q * 10000);
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return q;
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}
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/* Based on code by Douglas W. Jones found at
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* <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
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* (with permission from the author).
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* Performs no 64-bit division and hence should be fast on 32-bit machines.
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*/
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static
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int put_dec(char *buf, unsigned long long n)
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{
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unsigned int d3, d2, d1, q, h;
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char *p = buf;
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d1 = ((unsigned int)n >> 16); /* implicit "& 0xffff" */
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h = (n >> 32);
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d2 = (h ) & 0xffff;
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d3 = (h >> 16); /* implicit "& 0xffff" */
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/* n = 2^48 d3 + 2^32 d2 + 2^16 d1 + d0
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= 281_4749_7671_0656 d3 + 42_9496_7296 d2 + 6_5536 d1 + d0 */
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q = 656 * d3 + 7296 * d2 + 5536 * d1 + ((unsigned int)n & 0xffff);
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q = put_dec_helper4(p, q);
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p += 4;
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q += 7671 * d3 + 9496 * d2 + 6 * d1;
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q = put_dec_helper4(p, q);
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p += 4;
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q += 4749 * d3 + 42 * d2;
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q = put_dec_helper4(p, q);
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p += 4;
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q += 281 * d3;
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q = put_dec_helper4(p, q);
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p += 4;
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put_dec_full4(p, q);
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p += 4;
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/* strip off the extra 0's we printed */
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while (p > buf && p[-1] == '0')
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--p;
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return p - buf;
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}
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#define ZEROPAD 1 /* pad with zero */
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#define SIGN 2 /* unsigned/signed long */
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#define PLUS 4 /* show plus */
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@ -36,13 +113,7 @@ static int skip_atoi(const char **s)
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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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__res = ((unsigned long) n) % (unsigned) base; \
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n = ((unsigned long) n) / (unsigned) base; \
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__res; })
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static char *number(char *str, long num, int base, int size, int precision,
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static char *number(char *str, long long num, int base, int size, int precision,
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int type)
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{
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/* we are called with base 8, 10 or 16, only, thus don't need "G..." */
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@ -57,8 +128,6 @@ static char *number(char *str, long num, int base, int size, int precision,
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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 > 16)
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return NULL;
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c = (type & ZEROPAD) ? '0' : ' ';
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sign = 0;
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if (type & SIGN) {
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@ -83,9 +152,28 @@ static char *number(char *str, long num, int base, int size, int precision,
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i = 0;
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if (num == 0)
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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)] | locase);
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else {
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switch (base) {
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case 10:
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i += put_dec(&tmp[i], num);
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break;
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case 8:
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while (num != 0) {
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tmp[i++] = '0' + (num & 07);
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num = (unsigned long long)num >> 3;
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}
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break;
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case 16:
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while (num != 0) {
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tmp[i++] = digits[num & 0xf] | locase;
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num = (unsigned long long)num >> 4;
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}
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break;
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default:
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unreachable();
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}
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}
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if (i > precision)
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precision = i;
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size -= precision;
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@ -117,7 +205,7 @@ static char *number(char *str, long num, int base, int size, int precision,
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int vsprintf(char *buf, const char *fmt, va_list args)
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{
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int len;
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unsigned long num;
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unsigned long long num;
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int i, base;
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char *str;
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const char *s;
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@ -127,7 +215,7 @@ int vsprintf(char *buf, const char *fmt, va_list args)
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int field_width; /* width of output field */
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int precision; /* min. # of digits for integers; max
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number of chars for from string */
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int qualifier; /* 'h' or 'l' for integer fields */
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int qualifier; /* 'h', 'hh', 'l' or 'll' for integer fields */
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for (str = buf; *fmt; ++fmt) {
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if (*fmt != '%') {
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@ -191,6 +279,10 @@ int vsprintf(char *buf, const char *fmt, va_list args)
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if (*fmt == 'h' || *fmt == 'l') {
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qualifier = *fmt;
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++fmt;
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if (qualifier == *fmt) {
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qualifier -= 'a'-'A';
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++fmt;
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}
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}
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/* default base */
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@ -260,16 +352,40 @@ int vsprintf(char *buf, const char *fmt, va_list args)
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--fmt;
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continue;
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}
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if (qualifier == 'l') {
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num = va_arg(args, unsigned long);
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} else if (qualifier == 'h') {
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num = (unsigned short)va_arg(args, int);
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if (flags & SIGN)
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num = (short)num;
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} else if (flags & SIGN) {
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num = va_arg(args, int);
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if (flags & SIGN) {
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switch (qualifier) {
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case 'L':
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num = va_arg(args, long long);
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break;
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case 'l':
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num = va_arg(args, long);
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break;
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case 'h':
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num = (short)va_arg(args, int);
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break;
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case 'H':
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num = (signed char)va_arg(args, int);
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break;
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default:
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num = va_arg(args, int);
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}
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} else {
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num = va_arg(args, unsigned int);
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switch (qualifier) {
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case 'L':
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num = va_arg(args, unsigned long long);
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break;
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case 'l':
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num = va_arg(args, unsigned long);
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break;
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case 'h':
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num = (unsigned short)va_arg(args, int);
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break;
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case 'H':
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num = (unsigned char)va_arg(args, int);
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break;
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default:
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num = va_arg(args, unsigned int);
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}
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}
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str = number(str, num, base, field_width, precision, flags);
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}
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