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authorFlorian Weimer <fweimer@redhat.com>2022-12-19 18:56:54 +0100
committerFlorian Weimer <fweimer@redhat.com>2022-12-19 18:56:54 +0100
commite88b9f0e5cc50cab57a299dc7efe1a4eb385161d (patch)
tree2b733d221cc4247e16aef46150c2fc8153ad6db4 /sysdeps/ieee754/ldbl-128
parent46378560e056300623364669de2405a7182b064f (diff)
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stdio-common: Convert vfprintf and related functions to buffers
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>
Diffstat (limited to 'sysdeps/ieee754/ldbl-128')
-rw-r--r--sysdeps/ieee754/ldbl-128/printf_fphex_macros.h36
1 files changed, 7 insertions, 29 deletions
diff --git a/sysdeps/ieee754/ldbl-128/printf_fphex_macros.h b/sysdeps/ieee754/ldbl-128/printf_fphex_macros.h
index 28dccb1..bc712a2 100644
--- a/sysdeps/ieee754/ldbl-128/printf_fphex_macros.h
+++ b/sysdeps/ieee754/ldbl-128/printf_fphex_macros.h
@@ -36,45 +36,23 @@ do { \
zero_mantissa = (num0|num1) == 0; \
\
if (sizeof (unsigned long int) > 6) \
- { \
- numstr = _itoa_word (num1, numbuf + sizeof numbuf, 16, \
- info->spec == 'A'); \
- wnumstr = _itowa_word (num1, \
- wnumbuf + sizeof (wnumbuf) / sizeof (wchar_t),\
- 16, info->spec == 'A'); \
- } \
+ numstr = _itoa_word (num1, numbuf + sizeof numbuf, 16, \
+ info->spec == 'A'); \
else \
- { \
- numstr = _itoa (num1, numbuf + sizeof numbuf, 16, \
- info->spec == 'A'); \
- wnumstr = _itowa (num1, \
- wnumbuf + sizeof (wnumbuf) / sizeof (wchar_t), \
- 16, info->spec == 'A'); \
- } \
+ numstr = _itoa (num1, numbuf + sizeof numbuf, 16, \
+ info->spec == 'A'); \
\
while (numstr > numbuf + (sizeof numbuf - 64 / 4)) \
- { \
- *--numstr = '0'; \
- *--wnumstr = L'0'; \
- } \
+ *--numstr = '0'; \
\
if (sizeof (unsigned long int) > 6) \
- { \
- numstr = _itoa_word (num0, numstr, 16, info->spec == 'A'); \
- wnumstr = _itowa_word (num0, wnumstr, 16, info->spec == 'A'); \
- } \
+ numstr = _itoa_word (num0, numstr, 16, info->spec == 'A'); \
else \
- { \
- numstr = _itoa (num0, numstr, 16, info->spec == 'A'); \
- wnumstr = _itowa (num0, wnumstr, 16, info->spec == 'A'); \
- } \
+ numstr = _itoa (num0, numstr, 16, info->spec == 'A'); \
\
/* Fill with zeroes. */ \
while (numstr > numbuf + (sizeof numbuf - 112 / 4)) \
- { \
*--numstr = '0'; \
- *--wnumstr = L'0'; \
- } \
\
leading = u.ieee.exponent == 0 ? '0' : '1'; \
\