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e88b9f0e5c
vfprintf is entangled with vfwprintf (of course), __printf_fp,
__printf_fphex, __vstrfmon_l_internal, and the strfrom family of
functions. The latter use the internal snprintf functionality,
so vsnprintf is converted as well.
The simples conversion is __printf_fphex, followed by
__vstrfmon_l_internal and __printf_fp, and finally
__vfprintf_internal and __vfwprintf_internal. __vsnprintf_internal
and strfrom* are mostly consuming the new interfaces, so they
are comparatively simple.
__printf_fp is a public symbol, so the FILE *-based interface
had to preserved.
The __printf_fp rewrite does not change the actual binary-to-decimal
conversion algorithm, and digits are still not emitted directly to
the target buffer. However, the staging buffer now uses bytes
instead of wide characters, and one buffer copy is eliminated.
The changes are at least performance-neutral in my testing.
Floating point printing and snprintf improved measurably, so that
this Lua script
for i=1,5000000 do
print(i, i * math.pi)
end
runs about 5% faster for me. To preserve fprintf performance for
a simple "%d" format, this commit has some logic changes under
LABEL (unsigned_number) to avoid additional function calls. There
are certainly some very easy performance improvements here: binary,
octal and hexadecimal formatting can easily avoid the temporary work
buffer (the number of digits can be computed ahead-of-time using one
of the __builtin_clz* built-ins). Decimal formatting can use a
specialized version of _itoa_word for base 10.
The existing (inconsistent) width handling between strfmon and printf
is preserved here. __print_fp_buffer_1 would have to use
__translated_number_width to achieve ISO conformance for printf.
Test expectations in libio/tst-vtables-common.c are adjusted because
the internal staging buffer merges all virtual function calls into
one.
In general, stack buffer usage is greatly reduced, particularly for
unbuffered input streams. __printf_fp can still use a large buffer
in binary128 mode for %g, though.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
77 lines
3.0 KiB
C
77 lines
3.0 KiB
C
/* Print floating point number in hexadecimal notation according to ISO C99.
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Copyright (C) 2000-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef LONG_DOUBLE_DENORM_BIAS
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# define LONG_DOUBLE_DENORM_BIAS (IEEE854_LONG_DOUBLE_BIAS - 1)
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#endif
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#define PRINT_FPHEX_LONG_DOUBLE \
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do { \
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/* The "strange" 80 bit format on ia64 has an explicit \
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leading digit in the 64 bit mantissa. */ \
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unsigned long long int num; \
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union ieee854_long_double u; \
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u.d = fpnum.ldbl; \
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\
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num = (((unsigned long long int) u.ieee.mantissa0) << 32 \
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| u.ieee.mantissa1); \
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\
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zero_mantissa = num == 0; \
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\
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numstr = _itoa_word (num, numbuf + sizeof numbuf, 16, \
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info->spec == 'A'); \
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\
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/* Fill with zeroes. */ \
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while (numstr > numbuf + (sizeof numbuf - 64 / 4)) \
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*--numstr = '0'; \
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\
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/* We use a full nibble for the leading digit. */ \
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leading = *numstr++; \
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\
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/* We have 3 bits from the mantissa in the leading nibble. \
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Therefore we are here using `IEEE854_LONG_DOUBLE_BIAS + 3'. */ \
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exponent = u.ieee.exponent; \
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\
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if (exponent == 0) \
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{ \
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if (zero_mantissa) \
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expnegative = 0; \
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else \
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{ \
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/* This is a denormalized number. */ \
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expnegative = 1; \
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/* This is a hook for the m68k long double format, where the \
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exponent bias is the same for normalized and denormalized \
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numbers. */ \
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exponent = LONG_DOUBLE_DENORM_BIAS + 3; \
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} \
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} \
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else if (exponent >= IEEE854_LONG_DOUBLE_BIAS + 3) \
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{ \
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expnegative = 0; \
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exponent -= IEEE854_LONG_DOUBLE_BIAS + 3; \
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} \
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else \
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{ \
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expnegative = 1; \
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exponent = -(exponent - (IEEE854_LONG_DOUBLE_BIAS + 3)); \
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} \
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} while (0)
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#include <stdio-common/printf_fphex.c>
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