Commit Graph

4 Commits

Author SHA1 Message Date
Szabolcs Nagy c156098271 New expf, exp2f, logf, log2f and powf implementations
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
2017-10-13 10:58:00 +02:00
Corinna Vinschen 1f232abc89 Throughout, run newlib with -Wall -Werror option and fix bugs and
compiler warnings found this way.

	* libc/stdio/freopen.c (_freopen_r): Fix bug setting _flags.

	* libc/include/stdio.h (_rename): Define when building newlib.
	* libc/include/sys/signal.h (_kill): Ditto.
	* libc/include/sys/stat.h (_mkdir): Ditto.
	* libc/include/sys/time.h (_gettimeofday): Ditto.
	* libc/include/sys/times.h (_times): Ditto.
	* libc/include/sys/wait.h (_wait): Ditto.
	* libc/locale/lmessages.c (empty): Don't define for Cygwin.
	* libc/locale/lmonetary.c (cnv): Ditto.
	* libc/locale/nl_langinfo.c (nl_langinfo): Ditto for variable s.
	* libc/posix/collate.c: Throughout cast to avoid compiler warning.
	* libc/posix/engine.c (matcher): Initialize dp to avoid compiler
	warning.
	* libc/posix/glob.c: Disable on Cygwin.  Explain why.
	* libc/posix/regcomp.c: Fix "uninitialized" compiler warnings.
	(dissect): Deliberately silence gcc compiler warning.  Add comment to
	explain why.
	* libc/posix/wordexp.c (wordexp): Remove num_bytes variable since result
	is never used.
	* libc/posix/popen.c (popen): Ditto for variable last.
	* libc/reent/mkdirr.c: Include sys/stat.h.
	* libc/reent/renamer.c: Include stdio.h.
	* libc/search/hash.c:  Throughout use underscored variants of the stat
	function family.
	(init_hash): Add missing definition for the __USE_INTERNAL_STAT64 case.
	* libc/search/hash_bigkey.c (__big_insert): Add parenthesis to avoid
	compiler warning.
	* libc/search/hash_page.c (overflow_page): Initalize freep to NULL to
	avoid compiler warning.
	* libc/stdio/asiprintf.c (_asiprintf_r): Cast unsigned char * to char *
	to avoid compiler warning.
	(asiprintf): Ditto.
	* libc/stdio/asprintf.c (_asprintf_r): Ditto.
	(asprintf): Ditto.
	* libc/stdio/vasiprintf.c (_vasiprintf_r): Ditto.
	* libc/stdio/vasprintf.c (_vasprintf_r): Ditto.
	* libc/stdio/mktemp.c (_gettemp): Cast to unsigned char in call to
	isdigit to avoid compiler warning.
	* libc/stdio/vfprintf.c (_VFPRINTF_R): Initialize variables used for
	grouping to avoid compiler warning.  Only define and set nseps and
	nrepeats if they are really used.
	* libc/stdio/vfwprintf.c (_VFWPRINTF_R): Ditto.  Only define state if
	it is really used.
	* libc/stdio/vfscanf.c (u_char): Revert to be defined as unsigned char.
	(__SVFSCANF_R): Cast fmt in call to __mbtowc.
	* libc/stdlib/mbtowc_r.c (JIS_state_table): Disable when building
	Cygwin.
	(JIS_action_table): Ditto.
	* libc/stdlib/wctomb_r.c (__utf8_wctomb): Add parenthesis to avoid
	compiler warning.
	* libc/string/strcasestr.c: Deliberately silence gcc compiler warning.
	Add comment to explain why.
	* libc/time/strptime.c (strptime): Cast to unsigned char in calls to
	isspace to avoid compiler warning.
	* libm/math/e_atan2.c (__ieee754_atan2): Add parenthesis to avoid
	compiler warning.
	* libm/math/e_exp.c (__ieee754_exp): Initialize k to 0 to avoid
	compiler warning.  Drop setting it to 0 later.
	* libm/math/ef_exp.c (__ieee754_expf): Ditto.
	* libm/math/e_pow.c (__ieee754_pow): Add braces to avoid compiler
	warning.
	* libm/math/ef_pow.c (__ieee754_powf): Ditto.
	* libm/math/er_lgamma.c (__ieee754_lgamma_r): Initialize nadj to 0 to
	avoid compiler warning.
	* libm/math/erf_lgamma.c (__ieee754_lgammaf_r): Ditto.
	* libm/math/e_rem_pio2.c (__ieee754_rem_pio2): Ditto for variable z.
	* libm/common/sf_round.c (roundf): Remove signbit variable since result
	is never used.
2012-08-08 11:04:18 +00:00
Richard Sandiford 16740220a2 * libc/include/machine/ieeefp.h: Comment about new configuration
macros _FLT_LARGEST_EXPONENT_IS_NORMAL and _FLT_NO_DENORMALS.
	* libm/common/fdlib.h: Define new macros for testing floats.
	* libm/common/sf_*: Use them.
	* libm/math/ef_*: Likewise.
	* libm/math/sf_*: Likewise.
2001-04-04 13:33:01 +00:00
Christopher Faylor 8a0efa53e4 import newlib-2000-02-17 snapshot 2000-02-17 19:39:52 +00:00