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2012-04-11Merge remote branch 'nsz/master'Rich Felker-5/+6
2012-04-11optimize floatscan downscaler to skip results that won't be neededRich Felker-2/+3
when upscaling, even the very last digit is needed in cases where the input is exact; no digits can be discarded. but when downscaling, any digits less significant than the mantissa bits are destined for the great bitbucket; the only influence they can have is their presence (being nonzero). thus, we simply throw them away early. the result is nearly a 4x performance improvement for processing huge values. the particular threshold LD_B1B_DIG+3 is not chosen sharply; it's simply a "safe" distance past the significant bits. it would be nice to replace it with a sharp bound, but i suspect performance will be comparable (within a few percent) anyway.
2012-04-11simplify/debloat radix point alignment code in floatscanRich Felker-9/+4
now that this is the first operation, it can rely on the circular buffer contents not being wrapped when it begins. we limit the number of digits read slightly in the initial parsing loops too so that this code does not have to consider the case where it might cause the circular buffer to wrap; this is perfectly fine because KMAX is chosen as a power of two for circular-buffer purposes and is much larger than it otherwise needs to be, anyway. these changes should not affect performance at all.
2012-04-11optimize floatscan: avoid excessive upscalingRich Felker-27/+27
upscaling by even one step too much creates 3-29 extra iterations for the next loop. this is still suboptimal since it always goes by 2^29 rather than using a smaller upscale factor when nearing the target, but performance on common, small-magnitude, few-digit values has already more than doubled with this change. more optimizations on the way...
2012-04-11fix incorrect initial count in shgetc when data is already bufferedRich Felker-1/+1
2012-04-11fix bug parsing lone zero followed by junk, and hex float over-readingRich Felker-6/+5
2012-04-10fix float scanning of certain values ending in zerosRich Felker-1/+3
for example, "1000000000" was being read as "1" due to this loop exiting early. it's necessary to actually update z and zero the entries so that the subsequent rounding code does not get confused; before i did that, spurious inexact exceptions were being raised.
2012-04-10fix potential overflow in exponent readingRich Felker-1/+1
note that there's no need for a precise cutoff, because exponents this large will always result in overflow or underflow (it's impossible to read enough digits to compensate for the exponent magnitude; even at a few nanoseconds per digit it would take hundreds of years).
2012-04-10set errno properly when parsing floating pointRich Felker-4/+21
2012-04-10add "scan helper getc" and rework strtod, etc. to use itRich Felker-75/+115
the immediate benefit is a significant debloating of the float parsing code by moving the responsibility for keeping track of the number of characters read to a different module. by linking shgetc with the stdio buffer logic, counting logic is defered to buffer refill time, keeping the calls to shgetc fast and light. in the future, shgetc will also be useful for integrating the new float code with scanf, which needs to not only count the characters consumed, but also limit the number of characters read based on field width specifiers. shgetc may also become a useful tool for simplifying the integer parsing code.
2012-04-10unify strtof/strtod/strtold wrappers and fix initial whitespace issueRich Felker-34/+21
2012-04-10new floating point parser/converterRich Felker-94/+477
this version is intended to be fully conformant to the ISO C, POSIX, and IEEE standards for conversion of decimal/hex floating point strings to float, double, and long double (ld64 or ld80 only at present) values. in particular, all results are intended to be rounded correctly according to the current rounding mode. further, this implementation aims to set the floating point underflow, overflow, and inexact flags to reflect the conversion performed. a moderate amount of testing has been performed (by nsz and myself) prior to integration of the code in musl, but it still may have bugs. so far, only strto(d|ld|f) use the new code. scanf integration will be done as a separate commit, and i will add implementations of the wide character functions later.
2012-04-04math: fix x86 asin accuracynsz-5/+6
use (1-x)*(1+x) instead of (1-x*x) in asin.s the later can be inaccurate with upward rounding when x is close to 1
2012-04-01improve name lookup performance in corner casesRich Felker-2/+2
the buffer in getaddrinfo really only matters when /etc/hosts is huge, but in that case, the huge number of syscalls resulting from a tiny buffer would seriously impact the performance of every name lookup. the buffer in __dns.c has also been enlarged a bit so that typical resolv.conf files will fit fully in the buffer. there's no need to make it so large as to dominate the syscall overhead for large files, because resolv.conf should never be large.
2012-03-29math: minor cleanups in ceil and floornsz-10/+7
2012-03-29math: remove x86 modf asmnsz-111/+0
the int part was wrong when -1 < x <= -0 (+0.0 instead of -0.0) and the size and performace gain of the asm version was negligible
2012-03-29math: rewrite modf.c and clean up modff.cnsz-72/+45
cleaner implementation with unions and unsigned arithmetic
2012-03-28math: fix modfl.c bugnsz-1/+1
modfl(+-inf) was wrong on ld80 because the explicit msb was not taken into account during inf vs nan check
2012-03-27math: fix a regression in powl and do some cleanupsnsz-12/+11
previously a division was accidentally turned into integer div (w = -i/NXT;) instead of long double div (w = -i; w /= NXT;)
2012-03-27math: add dummy tgamma and tgammaf implementationsnsz-0/+32
2012-03-27math: remove comment about aliasing lgamma as gammansz-8/+4
It is probably not worth supporting gamma. (it was already deprecated in 4.3BSD)
2012-03-27math: fix typo in i386 remquof and remquol asmnsz-5/+5
(fldl instruction was used instead of flds and fldt)
2012-03-25Merge remote branch 'nsz/master'Rich Felker-15/+6
2012-03-25add strfmon_l variant (still mostly incomplete)Rich Felker-3/+27
2012-03-23asm for hypot and hypotfRich Felker-0/+87
special care is made to avoid any inexact computations when either arg is zero (in which case the exact absolute value of the other arg should be returned) and to support the special condition that hypot(±inf,nan) yields inf. hypotl is not yet implemented since avoiding overflow is nontrivial.
2012-03-23make dlerror conform to posixRich Felker-6/+16
the error status is required to be sticky after failure of dlopen or dlsym until cleared by dlerror. applications and especially libraries should never rely on this since it is not thread-safe and subject to race conditions, but glib does anyway.
2012-03-23minor rintl.c fix: remove unsupported ldbl format messagensz-2/+0
2012-03-23fix tgammal: don't set the signgam globalnsz-13/+6
(tgamma must be thread-safe, signgam is for lgamma* functions)
2012-03-22add creal/cimag macros in complex.h (and use them in the functions defs)Rich Felker-20/+9
2012-03-22acos.s fix: use the formula acos(x) = atan2(sqrt(1-x),sqrt(1+x))nsz-6/+2
the old formula atan2(1,sqrt((1+x)/(1-x))) was faster but could give nan result at x=1 when the rounding mode is FE_DOWNWARD (so 1-1 == -0 and 2/-0 == -inf), the new formula gives -0 at x=+-1 with downward rounding.
2012-03-22sysconf support for dynamic limits (open files and processes)Rich Felker-2/+9
2012-03-21initial, very primitive strfmonRich Felker-0/+77
2012-03-20x86_64 math asm, long double functions onlyRich Felker-0/+239
this has not been tested heavily, but it's known to at least assemble and run in basic usage cases. it's nearly identical to the corresponding i386 code, and thus expected to be just as correct or just as incorrect.
2012-03-20Merge remote branch 'nsz/master'Rich Felker-198/+127
2012-03-20upgrade to latest upstream TRE regex code (0.8.0)Rich Felker-1168/+1037
the main practical results of this change are 1. the regex code is no longer subject to LGPL; it's now 2-clause BSD 2. most (all?) popular nonstandard regex extensions are supported I hesitate to call this a "sync" since both the old and new code are heavily modified. in one sense, the old code was "more severely" modified, in that it was actively hostile to non-strictly-conforming expressions. on the other hand, the new code has eliminated the useless translation of the entire regex string to wchar_t prior to compiling, and now only converts multibyte character literals as needed. in the future i may use this modified TRE as a basis for writing the long-planned new regex engine that will avoid multibyte-to-wide character conversion entirely by compiling multibyte bracket expressions specific to UTF-8.
2012-03-20nearbyint optimization (only clear inexact when necessary)nsz-19/+29
old code saved/restored the fenv (the new code is only as slow as that when inexact is not set before the call, but some other flag is set and the rounding is inexact, which is rare) before: bench_nearbyint_exact 5000000 N 261 ns/op bench_nearbyint_inexact_set 5000000 N 262 ns/op bench_nearbyint_inexact_unset 5000000 N 261 ns/op after: bench_nearbyint_exact 10000000 N 94.99 ns/op bench_nearbyint_inexact_set 25000000 N 65.81 ns/op bench_nearbyint_inexact_unset 10000000 N 94.97 ns/op
2012-03-20remove a fixme commentnsz-3/+2
2012-03-20clean up pow.c and powf.cnsz-57/+43
fix comments about special cases
2012-03-20clean up powl.cnsz-92/+47
fix special cases, use multiplication instead of scalbnl
2012-03-20fix a cbrtl.c regression and remove x87 precision settingnsz-27/+6
2012-03-20optimize scalbn familyRich Felker-7/+46
the fscale instruction is slow everywhere, probably because it involves a costly and unnecessary integer truncation operation that ends up being a no-op in common usages. instead, construct a floating point scale value with integer arithmetic and simply multiply by it, when possible. for float and double, this is always possible by going to the next-larger type. we use some cheap but effective saturating arithmetic tricks to make sure even very large-magnitude exponents fit. for long double, if the scaling exponent is too large to fit in the exponent of a long double value, we simply fallback to the expensive fscale method. on atom cpu, these changes speed up scalbn by over 30%. (min rdtsc timing dropped from 110 cycles to 70 cycles.)
2012-03-19remquo asm: return quotient mod 8, as intended by the specRich Felker-17/+26
this is a lot more efficient and also what is generally wanted. perhaps the bit shuffling could be more efficient...
2012-03-19use alternate formula for acos asm to avoid loss of precisionRich Felker-3/+11
2012-03-19Merge remote branch 'nsz/master'Rich Felker-806/+655
2012-03-19fix exp asmRich Felker-23/+22
exponents (base 2) near 16383 were broken due to (1) wrong cutoff, and (2) inability to fit the necessary range of scalings into a long double value. as a solution, we fall back to using frndint/fscale for insanely large exponents, and also have to special-case infinities here to avoid inf-inf generating nan. thankfully the costly code never runs in normal usage cases.
2012-03-19code cleanup of named constantsnsz-623/+513
zero, one, two, half are replaced by const literals The policy was to use the f suffix for float consts (1.0f), but don't use suffix for long double consts (these consts can be exactly represented as double).
2012-03-19fix remainder*.c: remove useless long double castnsz-15/+6
2012-03-19don't try to create non-standard denormalization signalnsz-7/+4
Underflow exception is only raised when the result is invalid, but fmod is always exact. x87 has a denormalization exception, but that's nonstandard. And the superflous *1.0 will be optimized away by any compiler that does not honor signaling nans.
2012-03-19Merge remote branch 'nsz/master'Rich Felker-80/+3
2012-03-19new modff.c code, fix nan handling in modflnsz-44/+26