Based on code from https://github.com/ARM-software/optimized-routines/
This patch adds a highly optimized generic implementation of expf,
exp2f, logf, log2f and powf. The new functions are not only
faster (6x for powf!), but are also smaller and more accurate.
In order to achieve this, the algorithm uses double precision
arithmetic for accuracy, avoids divisions and uses small table
lookups to minimize the polynomials. Special cases are handled
inline to avoid the unnecessary overhead of wrapper functions and
set errno to POSIX requirements.
The new functions are added under newlib/libm/common, but the old
implementations are kept (in newlib/libm/math) for non-IEEE or
pre-C99 systems. Targets can enable the new math code by defining
__OBSOLETE_MATH_DEFAULT to 0 in newlib/libc/include/machine/ieeefp.h,
users can override the default by defining __OBSOLETE_MATH.
Currently the new code is enabled for AArch64 and AArch32 with VFP.
Targets with a single precision FPU may still prefer the old
implementation.
libm.a size changes:
arm: -1692
arm/thumb/v7-a/nofp: -878
arm/thumb/v7-a+fp/hard: -864
arm/thumb/v7-a+fp/softfp: -908
aarch64: -1476
In order to avoid the year 2038 problem, define time_t to a signed
integer with at least 64-bits. The type for time_t can be forced to
long with the --enable-newlib-long-time_t configure option or with the
_USE_LONG_TIME_T system configuration define.
Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
In case time_t is long, then the cast to long is a nop. In case time_t
is __int_least64_t, then the cast to long may truncate the value before
the division.
Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
In C++, the usage of static inline functions for getchar_unlocked and
putchar_unlocked may result in error messages like
error: ‘_putchar_unlocked’ was not declared in this scope
Fix this by not using the _getchar_unlocked and _putchar_unlocked
macros in C++.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Remove local strnstr() implementation to fix compile error:
newlib/libc/iconv/lib/aliasesi.c:53:8: error: conflicting types for 'strnstr'
_DEFUN(strnstr, (haystack, needle, length),
^
In file included from newlib/libc/iconv/lib/aliasesi.c:29:0:
newlib/libc/include/string.h:125:10:
note: previous declaration of 'strnstr' was here
char *strnstr(const char *, const char *, size_t) __pure;
^~~~~~~
Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
This reverts most of commit 979d467ff6e39ee5c52cf1aac7a6c9c63058141c.
We cannot avoid some bareword attributes until clang is fixed to
properly support __-decorated attributes; see this bug:
https://bugs.llvm.org/show_bug.cgi?id=34319
The macros in question expand to the empty string under gcc, so
only compilation under clang is affected, and since clang has the
bug, the obvious solution is to roll back the changes, and document
the issue.
Signed-off-by: Eric Blake <eblake@redhat.com>
- For prevent confuse about what BSD license variant we used, 2- or
3-clause license, we change the license to FreeBSD license to make
it unambiguously refers to the 2-clause license.
Always use the __-decorated form of an attribute name in public
headers, as the bareword form is in the user's namespace, and we
don't want compilation to break just because the user defines the
bareword to mean something else.
Signed-off-by: Eric Blake <eblake@redhat.com>
Add internal inline functions _getchar_unlocked() and
_putchar_unlocked() if __CUSTOM_FILE_IO__ is not defined. These
functions get _REENT only once. Use them for getchar_unlocked() and
putchar_unlocked(). Define getchar() and putchar() to these unlocked
internal functions if __SINGLE_THREAD__ is defined, otherwise use the
external functions to use proper locking of the FILE object.
Assumes that __SINGLE_THREAD__ is not defined if __CYGWIN__ is defined.
Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
This is copied from musl (MIT license). This is newer and more thorough
than that of FreeBSD currently shipped only on Cygwin.
Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
With this change the arm platform can now be fully compiled with Clang.
Tested by comparing the output with GCC 4.8.2, and Clang 4.0, using a
variety of arches, big/little endianness, and arm/thumb mode to verify
the generated assembly output matches between GCC vs Clang with UAL, and
also GCC with UAL vs GCC with non-UAL, for all preprocessor code blocks.
The only difference found is an extra nop at the end of the function
when compiled with GCC using armv7-a/thumb/little-endian/-O2 compared to
Clang. The nop is not emitted when compiled in big-endian mode.
